Microsoft claims that MOM 2005 with SP1 supports installing to SQL 2005. This is actually true, however none of these articles make reference to the fact that the tools on the MOM CD (either momcreatedb.exe or the setup wizard) will correctly create the database if run on x64 Windows. The tools will both claim that no SQL instances can be found and fail. There is a hotfix available (http://support.microsoft.com/kb/921278) which includes an x64 copy of momcreatedb.exe. A quick call to PSS and the call router can get you the hotfix. Note that this doesn’t fix the mom setup wizard, you have to use the momcreatedb.exe tool in the hotfix package.