i'm thinking of just getting a USB wi-fi card instead.. it'll be easier all round. Is there any advantage to go with a PCi one?
I personally use a USB Linksys Wireless 802.11B in my desktop. I like the USB better because it is easier to take to another computer temporarily, and if I end up getting a bad signal I can move the device around. Most of the time it is dificult to move the computer to get a better signal.

As far as using the digicell program, I have never used it, but I have been really happy with the wireless support on XP SP2. I even stopped using a wifi program that I paid for.
Good Luck
Jeremy