i agree, stick around outside Tong Ren Lu which is near The Portman hotel on Yan An Xi Lu, theres a load of bars with chicks in, best is as said before Judys or Manhattans (although Manhattans has gotten more and more ladyboys in over the last 3 weeks or so i have noticed)
There will be chicks on the street but be wary of them as they are freelancers and are not allowed in the bars....for what reason ? who knows but they are the ones most likely to rip you off once you have fallen asleep, if they get in your cab. just kick em out.
Also i suggest as "clubclass" said, DO NOT barter or do deals with local guys trying to sell "beautiful girl/massage/etc etc" as they are dangerous and more than likely you will be ripped off BIG TIME
Find your own chick and do your own negotiations, dont pay more than 800rmb, you can do deals the later it gets at night.
I had 2 hot little nymphettes for 900rmb at 4.30 last last weekend (although they did drain my fridge of orange juice and candys)
Good luck dude