Yes! I can confirm that Rock Band 1 drums will and DO work with GUITAR HERO: WORLD TOUR on the Playstation 3.
Today I found Rock Band 1 drums for $29.99 @ Futureshop. A GREAT price no matter how old the technology. If you can find the same deal or better, I urge you to pick up your own drum kit. Of course, this is if you already own Guitar Hero World Tour and guitar.