Online personals (or those you would find in City Paper)--caveat emptor. My success with them was alright, but there's nothing like just meeting that person accidentally.
See, you should start off slow. Slow in this case means picking up a college cutie. I see us hanging out in University City or on South Street in the near future.
After you get that out of your system, then you get that fine, mature, successful, in-need-of-sex thirtysomething.
Seriously though, you still need to take care of you first. Get yourself accustomed to having the house to yourself. Get some jobs lined up. Keep working on the diet. THEN worry about the ladies.