I currently have 3 PC's connected to one broadband connection and sharing files/printers wirelessly, and it does take alot of time to get get things right!
Most of my hardware is Linksys:
* Wireless Access point router * Wireless PCMCIA card
and my third computer has a Netgear PCI card.
With two PC's, you will only need a wireless access point and a wireless PCI card. The access point is connected to your host PC (via an ethernet adapter and a straight through CAT-5 network cable) and to your cable modem.
Once you have bought your hardware, the instructions are pretty self-explanitory. If you have any more problems then let us know :-)
By the way, my hardware may not neccessarily be the best option for yourself. I do believe you can get some hardware which connects via USB etc that I am not too clued up on