The latest version of TCPMP works with AVRCP (the bluetooth audio controls), however it is now called CorePlayer and costs $.
I've seen someone here write an app that will allow GSplayer to work with those controls, and GSplayer is free (and supports streaming audio, but not video). Its possible to adapt that to other players as well, but I haven't figured out how, and no one has made assigning custom commands to those keys an easy process (yet).
I use MortPlayer with my A2DP/ AVRCP headsets instead of WMP because its much more efficient, supports all my remote controls (and shuts the screen off to save battery after every keypress) and remembers where I was up to when I last closed the program (I hate it how WMP makes you load a playlist every time you open it!).
For streaming video, I just use TCPMP and don't bother with the remote controls... if I'm watching something on the screen, I don't mind pressing it. Remote controls for me are useful for music or any application in which the phone is tucked away somewhere. Why would you need it for video?
Well then, consider the thread hijacked. We now return to our regularly scheduled conversation.