I also purchase my Amidol and KBr from Artcraft - nice folks. You will also need Citric Acid.
You may want to check out my APUG Amidol thread. I made up a stock solution of Amidol in Propylene Glycol over a month ago and have been checking periodically for activity/stability. It shows no change, to date.
The advantage to using an Amidol stock solution is that I only have to handle dry Amidol once for several printing sessions that way.
I plan to contact print some 8x10 Efke 100/Pyrocat-HD negs on Azo tomorrow and develop in Michael Smith's Amidol Developer Formula, using my Amidol/PG stock concentrate. I'll let you know how it goes.