Hello Tracey.
One thing that kind of sucks about DNN is the plethora of unanswered questions that pervades these forums. (I have one for the User Accounts that has gone unanswered for weeks!) At the end of the day we are at the mercy of the project for support. Be that as it may, I have done what you are asking on a single server. I have a production instance and I needed to create a test/development instance. I am currently working on making a copy on a second server (a workstation class machine) so I can't directly help with that case right now unitl I have sussed it out for myself.
Here is what I did:
1) I made a copy of the existing dnn folder (dnn3013) and this is pointed to by virtual directory (dnn3)
2) I ran the backup (with verification) on the SQL Server of the dnn v3 db and this resulted in a back up file being created dnnv3bu
3) I then made a second copy of the current folder (copy of dnn3013) and pointed a new virtual directory (dnn3new) to that folder.
4) I restored the dnn v3 backup to a new name (this is all taking place on one server running W2K server IIS 5 and SQL server 2K) and this all worked fine.
5) I changed the web.config in the copy of the dnn3013 folder to point to the newly restored db.
6) Restarted IIS
7) I ran a SQL query to update the PortalAlias table with the new value. Restarted IIS (this was key...I believe IIS caches the DB info) and it works. Thank you. It took me some time to get the value just right, but it does work.
Anyway, that was all on a single server, which is not really what you want, but it may get you started...
Please feel free to reply with any questions.
Regards,
ltm