I don't know about your Asus. It may not post initially, but maybe a BIOS will fix it. I tried a Barton in an Asus that was SUPPOSED to be compatible with it and it didn't even post (BIOS issue), so I don't know how a legacy Asus board would act.
Just to make sure we're clear here.... You guys know that you have 266 MHz FSB boards and that Bartons require at least 333 MHz FSB, right? I mean, there's a lot of Barton's out on the net now that have unlocked multipliers, but who's to say the production Barton is going to be unlocked?