Since I found this thread on this topic, it should be noted that MS has two KB's regarding moving login accounts between SQL servers.

One KB is for moving logins between SQL7 to SQL2k or SQL2k to SQL2k

http://support.microsoft.com/kb/246133/

The other is for moving logins between SQL 2k5/8 to 2k5/8

http://support.microsoft.com/kb/918992/

The reason for the differences is because they changed some of there sysobject schema.

Cheers.

Bill