this your mobo?
it supports 266fsb max, so I think the fastest cpu you can fit into it is a XP2400+; not sure if a 2600+ amd was made with a 266fsb also, maybe. I think that cpu btw is a Throughbred B, but really its not important unless you are very interested in overclocking.
A XP2000+ is also fine for that mobo, but is at least in theory available in both Palamino (older) or Throughbred (newer). Again, unless youre overclocking, I doubt it matters much or at all to you. Probably it will still be a Palamino, although afaik AMD are in the process of, or are intending on, replacing all palamino production with throughbred. I guess the cpu you get will be either a Palamino if amd arent that quick at changing production for older models, and/or your chosen e-tailer hasnt sold off it's Palamino inventory yet. If amd are quick amd so is you e-tailer at flogging cpus, maybe it will be a Throughbred. Cant say what it will be and tbh i wouldnt really care even if it was for myself.
AFAIK:
XP1500+ to 2100+ : is or was available in Palamino, 133/266FSB.
XP1700+ to 2400+ : is or is intended to be available in Throughbred, A/B?, 133/266FSB. [Maybe a 2600+ t-bred too?].
XP2600+ to 2800+ : is available as Throughbred A/B?, 333 FSB.
XP2500+, 2700+, 2800+ and up : is or will be available as Barton, 333fsb,
edit: and
this thread might help you determine which youve got.