When we first released the Oracle Migration Assistant we had a ton of requests for other platforms.
The first was for Access migration, the challenge here is that Access includes an upsizing tool but it is not always viable, the latest version of Access does not neccesarily work with the latest version of SQL Server(this is the case right now where Access 2003 does not fully understand SQL Server 2005, the graphical designers are in read only mode etc) and also a lot of folks have Access databases in older versions (pre- 2003) and don't want to go through a double update, finally to use the Access wizard you need to have Access installed, which if you are just using Jet+MDB as a store is not always the case. Hence the SSMS team have been working on a new version for Access, you can get a CTP here.
Next up is support for Sybase, this is a big request as we see folks consolidating, moving away from Unix to Windows, or just seeing the value in SQL Server and thinking the migration should be easy, especially based on the shared history. You can get this CTP here.