That's a networking issue, you know. As Dr. DDS says, any wireless router will work with your PB. Here's why: standards. Apple is more standards compliant than just about any other computer maker, so if you get a complaint router (it's darn hard to find one that isn't compliant) all will be well. Look for "802.11b/g" and/or "WiFi" compliance on the box (they mean the same thing).
Case closed.