Connecting two computers on a wirreless network.

I have a Linksys WAG200G wireless router. I have a pc running vista ultimate and my dad has a Toshiba laptop running windows XP Home. Sometimes we want to send files to each other's computer without the headache of finding a usb and putting the files in there and then running to one end of the house. I need to know the exact steps of how to connect our two computers through my wireless router. Sometimes he needs to use the printer as well. So is it possible to share the printer as well? Thanx in advance.

Use the same workgroup name for both PC.