I have had oak bonsai for some time. This is my live oak this spring--Quercus virginiana "fusiformis." Texas-collected about 25 years ago. I got lucky back when there were more collectors in the Southern U.S.
You'll have to be more specific about what you're looking for.
Oaks are different on the east coast and west coast. West coast and desert oaks (Coast live oak Quercis agrifolia is probably the most commonly used oak for bonsai, second is cork live oak, quercus suber--a European species native to warmer climates there) can't really take eastern winters. Both of those species will need a lot of protection in your area. Do a search on either and "bonsai" and you will come up with many sources.
If you're after oak species native to your area, things are more complicated (And probably more expensive and harder to accomplish). A lot of eastern oak species aren't used for bonsai, because no one has taken them up. That's a shame. The most commonly used (which probably has the best characteristics for bonsai treatment) is Willow Oak Quercus phellos. It's native to the southeast in your area. It's relatively rare as bonsai, but there are collectors who have it.
Zach Smith, at
http://bonsai-south.com/ has been collecting and selling Willow oak for some time.
If you're after eastern "live oak" Quercus virginiana, you can find it, but not easily. I got mine from a collector in Texas back in the 90s. Not many people are selling it, now, although Zach has said he occasionally runs across it.
Don at
http://www.gregorybeachbonsai.com/ has some spectacular examples of live oak and even eastern white oak, but unless they'll set you back several thousand, not to mention another in shipping.