The others are correct, but before you buy the Asus AV7133 here is some food for thought.
It will not handle the upcoming Palomino CPU. Read overclockers.com article
here as the Asus AV7133 uses a lower quality voltage chip.
Also the Asus AV7133 uses the original A0 stepping of the KT133a chipset which is reported to have some trouble doing the 133/266 FSB thing. Abit KT7a is in the same boat here also using the A0 stepping of the KT133a.
Also the Asus uses a lamo software based audio Codec not an onboard audio CHIP!
Look into the Iwill KK266-R... it can handle the Palomino (with a BIOS update) uses an onboard audio CHIP, has an ISA slot, uses the A1 stepping of the KT133A chipset, and later if RAID does appeal to your usage for more than just another IDE port, the Iwill board uses the AMI controller chip which will do RAID 0, 1, and 10... not just RAID 0 like the Asus AV7-133.
I know Asus has a good name and reputation, uses high quality parts (generally speaking) but the AV7-133 just will not 'live' in your system as long as others like the Iwill. It simply does not have as much of tomorrows technology built into it. I mean the MB should be the center piece on which you build upon, and technology wise the Iwill KK266 will outlast the Asus AV7-133.