Once your YouTube account has been suspended, you will never be able to log back in (with that screen name). All of your videos will be taken down, or transferred to the correct copyright owner.
Sources:
http://www.google.com/support/youtube/bin/answer.py?hl=en&answer=141830
http://www.google.com/support/youtube/bin/answer.py?answer=57391&ctx=sibling
