Here's a couple of pics showing how I've been bending the tubes on bikes like the NAHBS (not) 29er and the GDR frame from last summer. Influenced by (ok, ripped off from) Steve Garro. It's about as low-tech as you can get, which suits me fine. First you get the right size piece of chromoloy, pack it full of fine sand, cap the ends with duct tape, and then pose for a pic while invoking your inner Dio. This part is most essential, if you can't contact your Dio, there's no hope for you.
Now strap that sucka onto a mandrel and heave! The bending in this pic (ignore the date, it was really last May) made both top tubes for the GDR bike as well as the seat tube for the fixie that's coming up. The key to bending like this is to make sure the radius is large enough- 24" in this case- and the tubing is the right diameter. Any thin wall tube larger than 1 1/8" really needs a pro tube bender to curve it without kinking. Smaller tubing like seatstays can be bent the same way on much smaller mandrels and you usually don't even need the sand.
Gonna be doing a lot more of this soon, seems everyone wants a sexy bike these days!