Like you, I got fed up with the battery dying part-way through extended gaming sessions, so I picked up a copy of the PS2 title SOCOM, which I got dirt cheap from the Amazon marketplace.
It comes with a Logitech USB headset, which works perfectly well with the PS3. Have a look
here - though my advice is to go for new, rather than used!
Cheapest I can see there at the moment for new is £15.24 + £1.99 shipping.