Why the PC for the wife? She not a MAC fan? DIVORCE HER!!! lol j/k I'm a fan of MAC, just not enough of one to plop the $$ for one. =)
I am unclear what you are asking for.
Are you looking for a site to explain networking? or one on how to share files from the MAC to PC?
If you are looking for the first then I would advise you to Google search - because there are some that go from giving just a basic insight to "OMG why do I need to know all this?" But I think what you are looking for is what do you need to network your computers together and the simple answer is a router. There are tons to choose from but the first choice is wired or wireless? From there its a matter of personal choice, I like Belkin but Linksys, D-Link and Netgear are all good choices. For home use the routers you are looking for will be called a router switch. They come with paperwork on how to connect them to your ISP modem and the computers.
If you are looking for sharing files between MAC and Vista, this site
should help. I have read a couple sites, on the site I posted at step 10, you may need to put the IP address rather than the name of the MAC. Try it both ways to see which works.