As far as I'm concerned, the guy got caught taking drugs, got banned and has served his sentence.
People should give him some slack. Rehabilitation is part of recovery and if he's doing ok now, then more power to him. I would let him run in the Olympics but I dont think thats going to happen. I read a part of his autobiography in the papers last week and he made a good point. Christine Ohuruogu, one of the gold medalists from the last Olympics missed three drug tests and was subsequently banned for a few years. When she came back, she won the gold and we all hail her as a British athlete!. If you miss 3 drug tests then as far as I'm concerned, your pretty much admitting to being on drugs!
Chambers went to his test and was caught. He's served his time. let the man run!
http://news.bbc.co.uk/sport1/hi/athletics/7931339.stm