Any way to make a Mac a wireless access point, wirelessly?

[M A V I C]

Doc wrote:
Waaaay back in the days before cable modem routers were commonly available, I ran IPNetRouter to make a virtual interface, permitting me to use a Mac as a router and NAT server without requiring a second Ethernet port. It might be possible to do the same thing on a modern Mac with WiFi.

Ha! I used to do the same with my performa 6230CD.