A beta version of MiKTeX 2.9 is now available. The main new feature is the integration of LuaTeX (see the relesae notes).

You can download MiKTeX 2.9 Beta here.

If you find a bug, then please write a bug report or post a message to the MiKTeX mailing list.

Bug fixes will be made available via the update wizard, hence I don't think that there will be second Beta. MiKTeX 2.9 will be released in October.