Amazon has announced a firmware update for the Kindle 2 and the Kindle DX that enhances battery life, provides native PDF support for the Kindle 2, and improves the PDF support of the DX. You can read more about it from Amazon directly here.
The biggest downside? That this doesn’t help the Kindle 1 owners at all. Needless to say, those of us that weren’t convinced that the few features added to the Kindle 2 were worth the full purchase price for the upgrade are not too pleased with the lack of support (read the comments in the above link.)