http://www.ati.com/online/mobilecatalyst

Thats a direct download to the newest Mobility Catalyst drivers for XP 32 bit, updated monthly. I've had it bookmarked for a while, and it's still working post AMD merger.

Laptops in general have worse support on drivers, but at least ATI seems to maintain a mobility driver you can get to with a bit of digging, and continues to support older cards. On the NVidia side, similar hacks to the installer doesn't mean it will work, as they may have just yanked support completely for the card with no notice.