Not really. elance.com has something, but you'd be working for pennies.

Just start calling around. I will assure you , though, that it ain't easy. Learning the software, buying all the stuff you need, is the easy part. Getting clients and keeping them happy is the hard part.

In the end, it's just a business like everything else. This means the marketing and management side will determine if you live or die in the field.

Good luck. I'd go buy a book on marketing from amazon, it helps some, and at least opens your eyes to the business side.

I just read "discipline of market leaders" by Treacy and Wiersema. It was ok. Just depends on your business background (I've got a minor in it, so this wasn't anything really new - most of business is common sense put to use).

I was doing this for awhile and I ended up getting most of my projects from previous employers. I don't mean they were referring other clients to me - I mean that they were outsourcing their firms' work to me. This worked pretty well for both of us. For them it was a good thing because they knew I understood their aesthetic and design methodology, had a working relationship with all their project managers, etc. For me it was good because I was able to make a better profit than when working for them fulltime, was able to make my own schedule, specialize in the type of work I was interested in at that point, etc.
I'd recommend contacting people you've worked with in the past (whether previous employers or those who've moved on to other firms) and tell them you're looking for this type of work. Ask them to keep you in mind and/or refer you to others.