Getting wireless internet on Mac Pro

I really need help as I've been trying to sort this out for a few weeks now. I bought a Mac Pro 2.55Ghz Dual-Core Intel Xeon recently but I got it without the airport extreme card inserted....WRONG DECISION!
Since then I've bought an apple airport extreme card separately (as per link http://www.lambda-tek.com/componentshop/index.pl?prodID=803639) and was planning to install it myself thinking that there would be instructions with it..Oh no, apple wouldn't make it that easy. Anyway I would be really grateful for an answer to 2 questions: 1) does anyone know if airport extreme cards are actually compatible with Mac Pro Intel Xeons and 2) do you know how to install them? I would need pretty basic instructions as I am not much of a techie, "only a designer"...thanks!!

hey, sorry I can't be of too much help, but I used to know a site that detailed EVERYTHING about opening macs, installing hardware etc. and they gave you a print-out with outlines for all the parts you have to take out like screws so you don't lose them or get confused ...I can't remember it now though I'm also unsure about what self-installation is allowed under warrenty! I know that installing an airport card on my mini voids it, so you should be careful!