Bitcoin version 0.5.1 is now available for download at: http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.5.1/
This is a bugfix-only release.
This release includes 13 translations, including 5 new translations: Italian, Hungarian, Ukranian, Portuguese (Brazilian) and Simplified Chinese. More translations are welcome; join the project at Transifex if you can help: https://www.transifex.net/projects/p/bitcoin/
Please report bugs using the issue tracker at github: https://github.com/bitcoin/bitcoin/issues
Project source code is hosted at github; we are no longer distributing .tar.gz files here, you can get them directly from github: https://github.com/bitcoin/bitcoin/tarball/v0.5.1 # .tar.gz https://github.com/bitcoin/bitcoin/zipball/v0.5.1 # .zip
For Ubuntu users, there is a new ppa maintained by Matt Corallo which you can add to your system so that it will automatically keep bitcoin up-to-date. Just type sudo apt-add-repository ppa:bitcoin/bitcoin in your terminal, then install the bitcoin-qt package.
Re-enable SSL support for the JSON-RPC interface (it was unintentionally disabled for the 0.5.0 release binaries).
The code that finds peers via "dns seeds" no longer stops bitcoin startup if one of the dns seed machines is down.
Tooltips on the transaction list view were rendering incorrectly (as black boxes or with a transparent background).
Prevent a denial-of-service attack involving flooding a bitcoin node with orphan blocks.
The wallet passphrase dialog now warns you if the caps lock key was pressed.
Improved searching in addresses and labels in bitcoin-qt.