Well, after a lot of help from the http://www.32feet.net/ forums, not forgetting Mr. Peter Foot himself, and late night messing, I've finally got a working version of my iTunes remote control (kinda) finished.
Ok, for those interested enough, there's a log window, which shouldn't dump out too much; volume controls work, but there's a bug in that once a volume or position value gets changed, messages start getting thrown back and forth- Once I've re-worked the request and response formats I'll be fixing the synchronisation issues. The format issue will also allow the playlist window to function by feeding from partial list messages.
There is also an iPod look-a-like dialog, which will in time provide full control. This will be waiting until after the other functions/bugs have been sorted out.
You can download the current version here: http://home.freeuk.com/eudoxus/BtChat.2007-07-07.001.rar
Again, thanks to everyone on the 32feet.net forums who helped!