I've uploaded release candidate binaries for Bitcoin versions 0.4.1 and 0.5.0 to SourceForge:
https://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.4.1/test/
https://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.5.0/test/
The 0.4.1 release is the old wxWidgets-based Bitcoin with a critical fix to the wallet encryption feature.
The 0.5 release is the new Qt-based Bitcoin (which also includes the wallet encryption bugfix).
Report bugs using the issue tracker at github:
https://github.com/bitcoin/bitcoin/issues