Greetings all,
thanks to those who posted the pdfsync details for TeXniscope and TextMate: it's now working really well for me. If anyone's having difficulties getting the TM->PDF direction working it might be worth noting that teh command posted above by Thomas should be only 3 lines long. That is, there is a comment, then a single line (containing the "&&"), and the rest is a single command on a single line. Just be careful to delete any line breaks when you paste the script into the command window.
For what it's worth, the synchronisation behaviour here isn't the same as Flashmode (a la Claus Gerhardt's work): the latter provides "real time processing" of the input file, so that you see what you're producing as you type. That is, the file is being processed behind the scenes, and changes to the pdf file are produced on the fly.
Cheers, Paul