Since GameRanger is rarely interesting these days, I've been playing some BF 42 and came across this site for the Forgotten Hope mod:http://macologist.org/
It's a big d/l (2 gb I think) and in spite of the instructions to use RARX decompress, stuffit seemed to work just fine. Be careful to point the installer to the BF directory or it will install in /applications, and not work at all.
Some of the maps push the frame rate down quite low on my 2 ghz G5, but mostly it runs well. Not so much jumping around and it's harder to get a kill, more difficult to spot enemies. A bit more tactical.