[ILUG-BOM] Windows/Linux IP forwarding?

Here's the situation:

Net DSL Windowsbox LAN(dhcp) Linuxbox

The LAN, naturally, has a 192.168.0.0 range of IPs (I think it's a class C). The DSL modem is connected to the Winbox on USB and the LAN is a 5-port hub supporting a windows network, with my Linux box (say hello to gort, folks) creeping in using dhcpd.

The Linux box, and any box on the LAN, can access everything. I think the Net cannot access anything but the Windows box on the DSL modem (see http://gort.cjb.net/. That's the Winbox.).

Now I need POP3 (and HTTP et al, if possible) access to the Linux box from the outside world. IP forwarding is enabled on the Winbox.

What do I do now?

PS: Can I get a static IP on the internal network with minimal changes to the other boxen?