Apple and AT&T have been hit with a $360 million lawsuit over the iPhone's Visual Voicemail feature.

A company called Klausner Technologies has filed a patent lawsuit under its visual voicemail patents, claiming damages and future royalties estimated at $360 million.

The lawsuit asserts that Apple's iPhone Visual Voicemail infringes Klausner Technologies' US Patents 5,572,576 and 5,283,818. The company claims to have successfully licensed these patents to various other companies, including for AOL, Vonage and others - though its licensing of technology to Vonage required a successful litigation in 2006.

The iPhone violates Klausner's intellectual property rights by allowing users to selectively retrieve voice messages using the iPhone's inbox display, the company claims.

The suit was filed by the California law firm of Dovel & Luner in a federal court in the Eastern District of Texas. "We have litigated this patent successfully on two prior occasions," said Greg Dovel of Dovel & Luner, counsel for Klausner Technologies. "With the signing of each new licensee, we continue to receive further confirmation of the strength of our visual voicemail patents."

Klausner Technologies describes itself as founded by Judah Klausner: "the inventor of the PDA and electronic organizer". Apple's original ground-breaking PDA, the Newton, was, in fact, covered under an OEM patent license granted by Judah Klausner over twenty years ago under his landmark US Patent 4,117,542.

Apple does not comment on pending litigation.