The Firebird Project team is happy to announce that the v.2.5.1 release candidate kits for Linux and Windows 32-bit and 64-bit platforms are ready for testing.
http://firebirdsql.org/en/firebird-2-5-1-rc1

MacOSX kits are delayed by a problem with MacOSX 10.7 (Lion) but should appear soon.

Enjoy! and please report bugs or regressions to the firebird-devel list.

Cheers,
Helen