Edited 20/9/05 to correct typos
As Paul Flessner says in his letter http://www.microsoft.com/sql/2005/productinfo/letter.mspx Database Mirroring won't make it in the RTM (Release To Manufacturing) release for SQL 2005. It will be there for people to test using a trace flag, but Microsoft has not declared it tested enough for production.
We do expect to see this feature go live sometime in the first half of next year.
Also Express Manager is being revamped. Its going to get its own Visual Studio lite appearance - also to come in the first half of next year.