What are you doing now for work? I would find a company that actually uses Unix and needs employees that can actually get around the system and can learn whats needed on the fly. Do you feel you're comfortable doing this? I'd think one of the ways to go about this is fine an employer that needs Unix support and get an entry level job there.
You will have to be open to doing other things outside of being a Unix admin as well. Employers a looking for the all-purpose sometimes so while you may be hired as a Unix admin, you may be in charge of other systems (Windows, Novell) etc., backup, hardware/software support. Just remember these things may come with the job.