AirPort (R) is nothing more than Apple's version of the industry-standard 802.11b standard (AirPort Extreme = 802.11g) The AirPort base station is mostly a collection of industry standards wrapped up in a nice Apple-style interface (with a large pricetag attached.)
The tech support people at your ISP may not know anything specifically about AirPort or Macs, but there probably won't be any techincal reasons why they won't work. For that matter, you could also use another company's base station (Linksys, for example, or D-Link, or whoever) with Apple AirPort cards in your computers. Your ISP might be more willing to help you with setting up one of those products.