The Athlon XP (Palamino core) can handle over 90 degrees C. I think it's rated to melt at about 92 or 93. Keep in mind that the temps you see from your motherboard are normally lower than the CPU core temp.
I've had mine running at 83 indicated for a few minutes without crashing. I've never had my CPU under continuous load long enough to hit max temp, but I think it would top out at about 85 degrees. It idles at 70. I have the POS stock cooler, and yes I have a heat problem.
My FSB is at 142MHz, with the default 1700+ multiplier of 11.