Klausner Technologies is suing Apple and AT&T over the Visual Voicemail service that is included on the iPhone. Klausner alleges that the voicemail service violates a number of its patents. It is also sueing Comcast Corporation and eBay and its Skype Voicemail for similar patent infringements.
At the heart of the lawsuit are US patents 5,572,576 and 5,283,818 which describe how users can access and manage voicemail messages using inbox displays.
Klausner, owned by private investors (shade of NTP here?) has already successfully licensed the same patents to Vonage and AOL (after similar lawsuits). It is now seeking over USD$300 million in damages and future royalties in the lawsuits.