The data/databases don't know or care if they are clustered. So you can
detach them from one machine and attach them to another with no problems.
However, you do need to be aware of these factors in a cluster:

* The databases (user and system) all have to be on a shared drive. If the
drive letter of that drive is different from the drive letter of the
originating instance, you have to take some extra steps which are outlined
in the KB article 314546 HOW TO: Move Databases Between Computers That Are
Running SQL Server http://support.microsoft.com/?id=314546.
* The SQL Server resource must be dependent on any drive with SQL Server
data or backups.
* If you plan to upgrade the existing instance to a clustered instance, you
can do so using setup as long as the data is already moved to a shared
drive. So create the Windows cluster, add a shared drive in its own group
that you plan to use for SQL Server, move all databases to that drive, then
run SQL Enterprise Edition setup to upgrade to a virtual server.
* If the virtual server name is different than the original server name,
run sp_dropserver/sp_addserver (local) to get @@servername correct. Note
that this only works when moving databases, not for renaming an existing
virtual instance. To rename an existing virtual instance you have to
reinstall with the correct name to get all the registry keys updated
properly.

Cindy Gross, MCDBA, MCSE
http://cindygross.tripod.com
This posting is provided "AS IS" with no warranties, and confers no rights.