This is a question that I hear many in the circles I run with[IT field as well] asking. The thing to remember about this is that all those unemployed IT workers who are not finding work are thinking the same thing. They are all looking to do their own thing so you will have plenty of company. Not saying you won't make it, but consider niches like Business Analyst or Reporting Analyst or some other skills that equate in making you stand out.
FWIW, I have done this exclusively for nearly that last 2 years (well since Sept '09). I was lucky in that I had a couple built in contacts, AND REAL LUCKY as my wife's company needed IT help during a move to an ERP/MRP package so I spent nearly a year doing just her company.
The problem doing that is while I focused solely on that, I let my looking for other jobs go by the wayside. Doing contract work, the key is to keep the gigs coming. So you must actively be working one gig while looking for the next if you want to keep working without gaps and dry spells. This is where I find myself now and find myself considering employment with an actual employer, IF I can even do that in a small town without much IT needs or on the road full time away from home
You also need to consider your rates you will charge, what you can get by on to cover not only the times when you are working but the times when you are actively searching for the next gig. Then there is filing for estimated quarterly taxes, social security, your own benefits like insurance. Its considerable work, but it does truly have its advantages! Most will agree, you are your very own best boss. Good luck!
Here are a couple links to get you started, its likely you have already been doing plenty of research but just in case you have not come across these
How to Set a Contract Rate | Monster
How to calculate your hourly rate as an IT contractor