Well, sp_dbcmptlevel is deprecated, so is sysdatabases.
ALTER DATABASE ... SET COMPATIBILITY LEVEL and sys.databases.
If you're using 2005 management studio to connect, it's not able to show compat mode 100, because that's newer than the tool is.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability