1. OSX firewall instructions: OSX Firewall settings for Tiger/Leopard. You'd probably need to do this for each of LimeWire & FrostWire. Make sure they are not using the same connection & listening ports. Check this via the program's preferences -> Advanced -> Firewalls.

2. Most important step about port forwarding is the very first one which you must do first: (a) Setting up a Static ip for OSX

(b) Can't find mac instructions but windows will be very similar: Port Forwarding for the Netgear DG834G ... make a note of the difference in ip given between the two however. Also for LW or FW settings, see Manual port forward instructions & sample image