Lightroom 2.5 and Camera Raw 5.5 are now available as final releases on Adobe.com and through the update mechanisms available in Photoshop CS4 and Lightroom 2. These updates include camera support for the following models:

Nikon D300s
Nikon D3000
Olympus E-P1
Panasonic DMC-FZ35**
Panasonic DMC-GF1
**Note that in Europe and Japan this model is marketed as the DMC-FZ38. Unfortunately, due to a metadata difference between these cameras, files from the DMC-FZ38 will not be supported until the next Camera Raw and Lightroom updates.

Release Notes:
Camera Raw 5.5 and Lightroom 2.5 include a correction to the demosaic algorithms for Bayer sensor cameras with unequal green response. Olympus, Panasonic and Sony are among the more popular camera manufacturers affected by this change. But the demosaic correction provides only a subtle visual improvement to the processing of those raw files.

Lightroom 2.5 corrects for the following problem in Lightroom 2.4. Lightroom 2.4 on Windows continued to display the import dialog when a memory card was detected regardless of the preference setting "Show import dialog when a memory card is detected."

Check:
http://www.adobe.com/products/photoshoplightroom/features/index.html

*** Version 2.4 ***
http://blogs.adobe.com/lightroomjournal/2009/06/lightroom_24_and_camera_raw_54.html

These updates include camera support for the following models:
Canon EOS 500D (Digital Rebel T1i/EOS Kiss X3 Digital)
Canon PowerShot SX1 IS
Epson R-D1x
Hasselblad CF-22
Hasselblad CF-22MS
Hasselblad CF-39
Hasselblad CF-39MS
Hasselblad CFH-22
Hasselblad CFH-39
Hasselblad CFV
Hasselblad 503CWD
Hasselblad H2D-22
Hasselblad H2D-39
Hasselblad H3D-22
Hasselblad H3D-31
Hasselblad H3D-39
Hasselblad H3DII-22
Hasselblad H3DII-31
Hasselblad H3DII-39
Hasselblad H3DII-39MS
Hasselblad H3DII-50
Kodak EasyShare Z980
Nikon D5000
Olympus E-450
Olympus E-620
Panasonic Lumix DMC-GH1
Pentax K-7
Sigma DP2
Sony A230
Sony A330
Sony A380
Note: Hasselblad support is for the 3FR file format only. The Hasselblad FFF file format is not currently supported.

Lightroom 2.4 Bug Fixes

The Lightroom 2.4 update includes several bug fixes. The following is a list of items FIXED in this release.

Web galleries with a Collection Title of six characters would not export or upload
The crop aspect ratio could revert to the last selected ratio even when reset to original
The crop aspect ratio in Quick Develop could be lost after a crop adjustment
The crop aspect ratio lock could be lost after an orientation switch
Images could preview incorrectly when imported using the MTP/PTP USB protocol
Sony .ARW files may not have been recognized by Lightroom’s import dialog
The Japanese language configuration of Lightroom on Mac OS X 10.5 could fail to switch to the print module if the HP B9180 was set as the default printer
Metadata options that are intended for use were dimmed incorrectly when exporting DNG files
The Japanese language configuration of Lightroom on Mac OS X was missing a shortcut for “Zoom Out”
Several translation and shortcut corrections were made for the eight additional languages introduced with Lightroom 2.3
New Lightroom 2.4 and Camera Raw 5.4 DNG Options

This release includes new DNG Compatibility conversion options. These choices help address the additional options available with the new DNG 1.3 Specification (http://www.adobe.com/dng):

Camera Raw 2.4 and later: The DNG file will be readable by Camera Raw 2.4 (Photoshop CS) and later, and Lightroom 1.0 and later
Camera Raw 4.1 and later: The DNG file will be readable by Camera Raw 4.1 (Photoshop CS3) and later, and Lightroom 1.1 and later. The DNG file will often be readable by earlier versions, depending on the camera model
Camera Raw 4.6 and later: The DNG file will be readable by Camera Raw 4.6 (Photoshop CS3) and later, and Lightroom 2.1 and later. The DNG file will often be readable by earlier versions, depending on the camera model
Camera Raw 5.4 and later: The DNG file will be readable by Camera Raw 5.4 (Photoshop CS4) and later, and Lightroom 2.4 and later. The DNG file will often be readable by earlier versions, depending on the camera model
Custom: (Not available in Lightroom 2.4)
Backward Version Option: DNG 1.1, DNG 1.3 (default 1.3)
Checkbox: Linear (demosaiced) (default unchecked)
Checkbox: Uncompressed (default unchecked)
DNG 1.3 Specification Update

The DNG specification has been updated to version 1.3.[LINK] The update includes the following changes:

In Chapter 2, “DNG Format Overview”, the section on Defective Pixels has been updated
The section on Opcode Lists has been added to Chapter 2, “DNG Format Overview”
The CFALayout tag has been updated in Chapter 4, “DNG Tags”.
Additional Tags for Version 1.3.0.0 were added to Chapter 4, “DNG Tags”
Chapter 7, “Opcode List Processing” was added.
“Appendix A: Compatibility with Previous Versions” was updated.
The additional "Opcode Lists" allow complex processing to be moved off the camera hardware, which can have limited processing power, and into the DNG reader, which is often running on more powerful hardware. This also allows processing steps to be specified, such as lens corrections, which ideally should be performed on the image data after it has been demosaiced, while still retaining the advantages of a raw mosaic data format.

*** Version 2.3 ***
http://blogs.adobe.com/lightroomjournal/2009/03/lightroom_23_and_camera_raw_53.html

These updates include camera support for the following models:(Previously provided in the release candidates of these updates)

Nikon D3X
Olympus E-30
This update also includes preliminary support for the recently announced Epson R-D1x (and R-D1xG).

The Lightroom 2.3 update includes several bug fixes.

FIXES originally provided in the Lightroom 2.3 Release Candidate

In the Windows 64-bit version of Lightroom an sFTP upload process could cause Lightroom to crash.
Slideshows could return to the first image randomly during playback.
A memory leak could cause Lightroom to crash while attempting to process files with local adjustments.
Canon EOS 5D Mk II sRAW files could process with artifacts in Lightroom 2.2.
Lightroom 2.2 could cause disc burning to fail for Windows customers.
FIXES new to the final version of Lightroom 2.3

Attempting to undo(CTRL-Z) a single step in Lightroom 2.2 on Windows could cause a series of previous actions to be undone.
Lightroom 2.3 now provides language support for the following additional languages:
(UPDATE: Use this link to download the new language versions It indicates a trial version but it's identical to what we're now shipping from the Adobe.com Store for this new version. Since technically these versions didn't exist before there was no place to put them on the Update page.)

Chinese (Simplified)
Chinese (Traditional)
Dutch
Italian
Korean
Portuguese (Brazilian)
Spanish
Swedish