CareerBuilder (profile; site) has just bumped up its coolness factor and raised the stakes in the competition to be the No. 1 job board in the U.S.

Soon, jobseekers with an Apple iPhone (the epitome of techno-cool) can search for a job on their phone as easily as on their MacBook. And actually, it might even be easier, since CareerBuilder uses the iPhone’s geolocation to identify your city. All you do is enter the relevant keywords and up pops a list of jobs. Scroll the list, jump back and forth, narrow the list with more keywords or change location, should you decide Las Vegas would be more fun than Topeka.

Once you find a job that interests you, select it and CareerBuilder emails you the link so you apply when you get home. More than one job of interest? Add it to your favorites and you get sent the whole list.

Check out the online demo to see for yourself how it works.

CareerBuilder’s Jennifer Grasz tells us the service will launch any day now and when it does, all jobs on CareerBuilder.com will be accessible. Employers don’t pay extra and jobseekers pay only for the data transfer, according to their ATT contract.

Although iPhone users represent a small percentage of mobile users in the U.S. (in part because of Apple’s deal with only one carrier, ATT), they are among the heaviest consumers of mobile content. How extensively they will use the new service is anyone’s guess. “We are getting in the door early to tap into the potential of a user base that is expected to grow at a substantial rate,” Grasz says.

Mobile job searching and even applying is more common in other parts of the world, especially in Asia where cell phones are more common than landlines and personal computers.