You shouldnt have a problem with it at all. I have a P3 on a different motherboard, and I have run it on PC100 ram and not had a problem. As long as the board can run the ram at 100 and the P3's frontside but at 133, I dont see that big of an issue. You wont have the full potential of the cpu, but it should still run very well.
My only question is why dont you get a board that can run the ram at 133 instead?
It is a 440BX based board and BX boards have been know to overclock to 133MHz FSB and run totally stable. The only catch is, unless there's an AGP divider and PCI divider, the AGP and PCI buses will run way,way,way outta spec.
If you dont want to get a new mobo, just make sure your bios is the latest.

I have the same motherboard and I recomend a 850 p3 with a 100MHz FSB with that motherboard ($197 at egghead.com). I had p3 600 with a 133MHz FSB and could only run it at 550, the AGP video card didnt like the bus speed. My 850 runs stables at 940 with no extra cooling and generic PC100 ram.

I agree with wiyot. I tried to run a 133fsb P3 800 on my abit be6-2 but the agp and pci busses get pretty high at that fsb. I had a lot of probs (agp= 2/3 * 133 and pci 1/4 * 133 which is both too high, but are the only settings on this mobo) + the memory always runs at the same speed as the cpu bus on this card, no way to put it at 100 MHz.
So a P3 with a 100 Mhz bus is the way to go and you will be able to overclock this baby >< P3 at 133 almost not overclockable cuz of the ram and agp/pci bus.

Thanks for the help. I guess I will go with the 850 instead. So in other words this will be the last CPU I will be able to run effectively on the board since the rest are all going to be on 133 FSB?

Well, theoretically, any slot 1 cpu that runs at a 100MHz FSB could be run on that board. So you *could* run a 1GHz P3 on it, but Im not sure those are there. I havent kept up on the latest P3's and the FSB variations.

I have the exact same board myself. Out of all the mobo's I've used, and there have been many I have enjoyed this one the most. But I have not seen any p3 above 850 that runs on a fsb lower then 133. So it appears that our options have run out. The only option I see is the good old (crap) Celeron II. There is an 850 version out apparently, not sure of the o/c capabilities of this one but hopefully, intel will throw out a few more which will give the BX a little more life yet. I know the celery's are hopeless standing next to a P3 but because of the o/c abilities they do have a use.
 
(god I hate this new forum software) the ubb 6.0 at least looked ok)
 
- Card

Yeah, unless you want a cheap Intel overclock, the Celeron is worthless. The Duron 600 is comparable to the Celeron 800. Other than that the Celeron gets slapped silly by AMD. The Duron is closer in performance to the Pentium 3, and a hell of a lot cheaper than the Celeron or P3.
Unless you plan on overclocking, yeah, stay away from the Celeron.