I have a monowall pc-cdrom version running on a box with the following 
specs:
AMD Athlon XP 2600
512MB DDR Ram

Configured on my m0n0wall are three interfaces with space for two more 
in the future:

LAN - 192.168.1.1/24
WAN - X.X.X.X
OPT1 Interface
OPT2 Interface (Not Used)
OPT3 Interface (Not Used)

The Local Network Connects Out through the WAN Interface (Around 13 
computers) natted out via 1 ip.
The OPT1 Interface Connects Out through the WAN Interface as well 
(Around 300 Users at once) natted out via 3 ip's

Now with this configuration my network really just needs more than the 
approximate 4000 NAT table entries that ive heard.. Has anyone managed 
to recompile the kernel with the number of NAT entries significantly 
increased?