Microsoft Local Group’s Erik Jorgensen thinks “the majority” of local access will be from mobile devices in five years. My gut tells me that mobile access may not dominate quite so quickly.

But whatever the timetable, it suggests a sea change in local advertising models. It also suggests a stronger role for telecom players in serving mobile and IP-based content: whether they are traditional carriers, or just as likely, portals providing VoIP, PSTN and instant messaging services over mobile.

The impact on local usage and advertising will be a big one. And the seeds are being laid. As Issac Kato of General Catalyst Partners noted at the Kelsey ILM conference in early December: “Wireless is inherently local….when you do mobile search, pay-per-call becomes trivial.”

Already on the bandwagon is Yahoo!, which has gotten Intel Centrino to sponsor the keyword, “WiFi Hotspots,” which is a top local search.

AOL has more to discuss. Its AOL Instant messenger already pushes more text messages than any wireless carrier. In addition, its MapQuest unit reports “hundreds of thousands” of mobile users. AOL will clearly seek to leverage that usage to provide a suite of additional, local-oriented data and telecom services.

The synergies are so apparent that at the Kelsey event, AOL’s top messaging executive, Chamath Palhapitiya (who has since joined a venture firm) derided the idea that AOL should try to limit itself to becoming a “telco.” “I don’t think so,” he said. “They have a half-life. Being in a telco…is a very marginalized business,” especially given the persistence of wireless use in urban markets by younger people.

Instead, AOL will focus on leveraging its customer relationships and its customer data to mix n’ serve a wider range of telecom and data-oriented services, including content, calls, emails and instant messages. Most interestingly, it will try to jumpstart its telecom efforts by providing a free PSTN number at the beginning of 2006. In 12-13 months, AOL thinks it will introduce call-related advertising via geo-targeting, age and zip code – although Pailhapitiya acknowledged that advertisers have “de minimus” interest right now.

Ultimately, Pailhapitiya expects to see “more action on PC to PSTN” than on VoIP, which currently has about three million users in the U.S. “It complements mobile plans,” he said.