Although three-way and dimmable CFLs were fairly exotic just a year ago, they're now widely available from home centers, megamarts, and online retailers. The problem is their complex internal wiring makes these bulbs pricey at $10 to $15 a pop. And you don't want a cheap knockoff. It'll be oversized, offer harsh light, and may not move smoothly between brightness settings. Earthtronics
offers good three-way CFLs, as well as dimmables for all types of fixtures.