Most linksys routers can do it. (imo the best networking hardware company around, up there with D-Link and Cisco)
Netgear can do it but i've heard nasty stuff about them.
Also note that the D-Link can only forward 1 port at a time. (If you don't want to forward the 31 op2 ports, just forward 47800 UDP and that's enough to join other people's games).