Surprising exactly nobody, Nokia put the Apple iPad in its sights in its ongoing battle against Apple for patent infringement. Nokia originally sunk its legal hooks into Apple back in October, 2009, when it sued Apple in the United States District Court in the District of Delaware for violating many of its patents relating to GSM, WiFi, and UMTS.
The suit itself was put on hold back in March pending an International Trade Commission investigation arising out of complaints filed by both parties, in which hearings are scheduled to be held in October and November. But just to keep things interesting, Nokia went ahead and filed a complaint in the United States District Court in the Western District of Wisconsin to add the iPad 3G to its list of infringing Apple products.
Why Wisconsin? Well, Nokia and Apple pretty much have their choice of venue, doing business all over the United States. It's likely that this particular district represents a blend of court rules and precedent that favor Nokia in some way.