After skipping MC 1.2.4, BuildCraft for Minecraft 1.2.5 is ready for release (And I really hope there will not be a MC 1.2.6 in the near future)
Like the previous release this is pretty much a straight up port for MC 1.2.5, however there are some significant under-the-hood changes. ModloaderMP is no longer required for neither the client or server and Buildcraft 2.2 has been ported to use the netcode provided through Forge. Due to the major changes, chances for bugs are higher in this release compared to previous releases.
Modloader is still required, as is forge (tested with version 126.96.36.199, newer versions might work)
BuildCraft 3.1.5 for Minecraft 1.2.5 (SSP)
BuildCraft 2.2.14 for Minecraft 1.2.5 (SSP/SMP)
Report bugs on the forum!