Any wireless (802.11b) device will work with AirPort. {canned statement}AirPort is Apple's trade name for their implementation of the IEEE 802.11b standard, therefore any and all 802.11b equipment will work fine with AirPort equipment.{/canned statement} There is one caveat; setting up WEP with different vendors' equipment can be a hassle because of inconsistent terminology in the instructions not problems in the technology.
The only platform specific issue with Linksys products is that some of them use a configuration program, always written for PCs. The number of such products is falling steadily, as more and more come out with browser-based configuration utilities. Your Linksys wireless router (a BEFW11S4?) should be accessible via your browser. To do this, set your computer to get an automatic IP address (that's called DHCP), then turn it off. Plug it into the router and turn on the router, then your computer (this ensures that you'll get an address from the router, and thus be able to connect to it). Open your browser and enter 192.168.1.1 in the address window, and connect-you'll get the setup pages for the router-they're all just like in the book.