Did exactly that a couple of weeks ago. I had some initial problems with the security settings in XP Pro (thanks to the folks on here who sorted me out).
The wireless networking worked "out of the box", with a second-hand Netgear wireless access point connected to the existing ADSL 4-point router, and an 802.11b card for the laptop.
It really was easy. I turned on WEP once I'd got it working, and that too was easy.
Now I sit downstairs, in the lounge or in the kitchen, and do the e-mail on the laptop. Way to go!