As for places that sell used bikes in philly, check out Via at 9 & South and Firehouse at 50th & Baltimore. They usually don't keep a lot of SS or fixed bikes in stock but they'll be happy to whip something up for you. Or buy a geary and convert it yourself. Oh yeah, keep an eye on craigslist too. There have been a lot of SS/fixed bikes on there lately. Maybe everyone is getting rid of their summer toys =]

I dont know a whole lot about the Alpha, but I'll tell you what I do know. They come with really low-end components - they have to for what he's chargin. But from talking to the owner, I got the feeling that he wasn't just trying to pass off cheap crap on people. He just wants to sell simple bikes that work without a lot of whizbang stuff. Anyway I don't necessarily think the Alpha is a bad choice. It will get you around for awhile, but I wouldn't bother upgrading anything unless it completely breaks. Instead save that cash for a nicer ride.

I've know a few people who have Langsters and they seem ok with them for what they paid. The biggest complaints I have heard about are the pedals and seat which are easy swaps. Search around here for other opinions.