Did you know that if you plug a regular old USB printer into the USB port on an Airport Express base station, it will show up on your home network? You need to turn on Rendezvous, which is built into the Mac OS. As soon as you do that, voilá! The printer shows up in your printer control panel and everyone on your wireless network can access it.
We hadn't know this would work, but I noticed the USB port on the base station and had a chat with a friendly technician at the Apple Store on Orchard Road. He confirmed my suspicions and we were able to buy a Canon Pixma IP4200 instead of purchasing the more expensive wireless model or passing the printer cable back and forth when we need to print. Gotta like that!