The short version is that networking is what gets you Unix admin jobs. There are very few times I've ever heard of somebody getting a job through a want-ad, online posting, or anything like that. It is almost always either referrals or recruiters who hook you up.

Here's the longer verison:

The most important (and for somebody just trying to break into the field, hardest) step is to get to know people in the field. The first IT job I got was as a help desk analyst and I found that answering a web job posting from a contracting house. From that point on every single job I've gotten and almost every interview I've gone on has come from either a recruiter I knew or a referral from somebody that knew of the opening.

The best bet is to find one or two IT recuriters in your area and talk to them. Introduce yourself as somebody trying to break into the field and let them interview you. They will know the market in your area, and reputable ones will give you advice and help even if you don't fit any of the specific openings they have currently. They make their living knowing admins to place in jobs. Thus they are usually pretty receptive to meeting new people. And doing you favors when you're getting started can come back to help them later. I've gotten jobs from being called months after visiting with a recruiter about something completely different, just because they remembered me from that initial visit.

I know nothing of Detroit, but a couple of the national IT firms are RHI Consulting and Sapphire Technologies. I've talked to recruiters from both and found them acceptably good. That might be a place to start. My favorites have all been from smaller local shops though. If you know any Unix admins ask them what recruiters the've worked with and would recommend, anybody in the field a while will know some. That way you might get exposure to some of the local recruiters that will know the market in your city best.