Those are two very different questions. Are you just trying to get I-DEAS data into Teamcenter, or are you also wanting to migrate the I-DEAS data to NX?
The answer to the first question is that you'll need to migrate the I-DEAS PKG file to Teamcenter via the Teamcenter Integration for I-DEAS (TcII) module. This will get I-DEAS data into Teamcenter.
The answer to the second question is that you can use CMM (Content Migration Manager) to migrate the I-DEAS to NX format.
There's a whole methodology and lost of configuration setup to do this correctly without a lot of problems along the way.