Hawaiian company GPNE claims to hold patents on GPRS data transfer, and according to AppleInsider it's named Apple, RIM, Nokia, Sony, and Amazon in an infringement lawsuit. GPRS is a (much) slower form of data transfer available on all of Apple's iDevices; if you live in the U.S., chances are you've never even connected to GPRS on your iPhone since faster EDGE networks are fairly widespread. Other countries without nationwide 3G coverage and no EDGE to speak of (like New Zealand) have extensive GPRS coverage.
GPNE has accused Apple and other defendants of infringing on three separate patents. Oddly, all three patents have only recently been awarded: two in 2009, and one in 2010. GPRS has been around for far longer than that, however, and was standardized by the European Telecommunications Standards Institute, so it's unclear how a Hawaiian company can reasonably assert patents over the technology.
GPNE has asked for post-judgment royalties should the court decide in its favor. Specific devices named include the iPad, iPhone 4, Amazon Kindle, Barnes & Noble's Nook, and the BlackBerry Torch 9800, but according to AppleInsider the patent claim is worded broadly enough to apply to any 3G-capable device.