Seattle-based Cequint is gaining traction. The company’s City ID, an enhanced caller ID feature, is being preloaded on handsets offered by U.S. Cellular. That brings Cequint’s publicly announced carrier customers to three; it already has deals with Alltel and Verizon Wireless.

In what Cequint executives describe as an incredibly simple idea, City ID displays the location – city and state – where an incoming phone number is registered. That provides enough information for customers to get a clue about who’s calling them.

Unless an incoming caller is saved into a mobile phone’s address book, subscribers only have a number to try and guess who’s calling them, explained Edward Perez, senior director, product development and management at U.S. Cellular, in a press release. City ID gives U.S. Cellular subscribers that additional piece of information that helps identify the caller.

The application will be available on the LG UX585 and Samsung Delve R800. U.S. Cellular subscribers will receive a complimentary 15-day trial of the application beginning with the first incoming call. Customers can subscribe to City ID for $1.99 per month or a one-time purchase of $34.99 added directly to their bill.

MetroPCS launched a similar service with TargusInfo as its partner in October.