Nightlife in Shanghai

Me and a friend are going to Shanghai from Beijing today.
How is the nightlife in shanghai? We would like to know some good places to party at, nice discos or bars.

During our time here in Beijing we have often been told if we want to go to a "girl bar" what is that?
And some girls are offering massage to us, are they the prostitues of china? or is it a "normal" massage?
:blush:

Lots of qustions here, but china is pretty different from where i come from, good to know some things so you dont do anything stupid.

Cheers :-)