I've done this before...Like This:

1.  Shut down the SQL Services MSSQLSERVER and SQL Server Agent on both boxes.

2.  COPY the database files (.mdf .ndf, .ldf) from old server to new server, placing them in the same directory names on new server.  Master and msdb should overwrite on new server, and tempdb doesn't need to be copied. 

3.  Start the services back up.  Voila!

If something goes wrong (which it didn't for me), since you did a copy, the old server is still operational.  This method can take some time if the databases are large and the network speed is not...but using this method you can run a full "test" of the process during off-hours without affecting the old server.

4.  You'll need to do some hand-checking for hard-coded server names in the code and in DTS packages, etc. and backups, if to disk shares, may need to change.

This can be a tricky operation...should have some SQL experience to avoid pitfalls.

Steve