Keith, enter "annealing" in the search window and you will get lotssa info...
my technique.....
1) use a propane(or MAPP) gas torch with a large head...I used the pistol grip version from HF
2) VERY LIGHTLY soot a stripe down the piece to be annealed(the whole piece doesn't need to be covered in soot)....remember that you only haveta anneal the part that actually bends...not the whole piece
3) while steadily moving the torch back and forth, heat up a section until the soot disappears...as the soot disappears, the flame turns orangish...keep on moving down the piece as that section is now annealed and will blister or melt if it gets too hot...on an angles, I aim the torch towards the "break" of the angle...a large headed torch will help disperse the flame
4) allow ample time to cool...the aluminum will reharden if you work it back and forth (work hardened)and can be re-annealed if needed...
5) get some scrap and practice...including heating to the melting point...just because...
6) I found that using a bending jig and bending slowly and using a rubber or dead blow hammer along with a hardwood dolly will give very satisfactory results...work on short sections at a time...you can also screw it down and install as you go, using a rubber mallet to "massage" the piece as needed
7) GOOD LUCK and have fun...learning a new skill is always a rewarding challenge
madjack
P.S. I have some pics of the process in my Yahoo picture album...just click the WWW button at the bottom of my reply...