Most petstores will carry a few pieces, but in general I've found they don't carry a large selection of real wood. You can order the stuff online, but at most places I've found they don't give you a pic of the actual piece you're ordering, just an example. To me, with wood, I want to know what it looks like.
I recommend you keep watching ebay, as you can see what you're actually bidding on. I've gotten several pieces from there.
As far as a pot, my wife found a 21qt stock pot at walmart for $19 that's about 13 or 14 inches wide and is accomodating a very large piece of wood that I'm currently boiling. it's not very tall, so I'll have to boil the bottom, then put it in upside and boil the top, but it really hurries the process along compared to just soaking.
Another option is to get a tub to soak it in, then repeatedly boil water and put over it, so instead of just changing the water every day, you change the water with boiling water. not as effective as boiling directly, but it still works a little quicker than just using warm/hot water.
If you get a large piece, and don't boil, the larger the piece the longer it'll take to soak out the tannins. Don't plan on 2 weeks, cuz it may be much longer than that.
You're other option is to do what you need to do to kill any possible living organisms on it, like a peroxide dip, then put it in your tank. It will stain your water, giving it a brown or yellowish tint, which isn't bad for your fish if you don't mind the water not being clear.
Just my $0.02
