OK, if you want to connect more than one PC, you should use a router. Most wireless routers will also allow wired connections.
Thus you wire between the STB/Cable Modem and Router.
From the router you have the option to hardwire or go wireless, or both.
Individual PCs can thus connect to a wireless router by having their own wireless adaptor card (some modern PCs and especially laptops may already have this built in). Or you can connect via ethernet cable between the router and PC.
If you only use an access point, in place of the router, the system should work, but you would only be able to use one PC at any one time.
If buying today I would recommend you go for the "g" rather than older "b" standard wireless. It works faster. "b" kit will generally work on "g" networks, but only at the "b" speeds.
The sketch attached to this post shows my combination network setup:
http://www.cableforum.co.uk/board/sh...9&postcount=11