Apple has a case on this, but only for really the dumbest of reasons. Samsung pretty blatantly ripped off several of Apples icons, which apparently Apple trademarked. Apple is trying to use this OBVIOUS infringement on their trademark to build a bigger case against Samsung with MUCH more ridiculous claims, such as Samsung is violating one of their patents of having a rectangular device with curved corners.
Basically patent law is stupid, and it needs to die. Apple and Microsoft patent EVERYTHING, and they are doing their best to kill Android with patents. They aren't going after Google directly, but instead suing device manufacturers to make Android (free OS) have an associated cost. Microsoft has already done this with HTC, and literally makes them buy a license for each Android device they sell. Microsoft charges them more for this license than Microsoft charges for its ENTIRE Windows Phone 7 OS, which is blatantly ridiculous. Apple is trying to go after the lowest hanging fruit they can on this one, which is Samsung, as they OBVIOUSLY have infringed on certain trademarks. The goal is to take this obvious infringement and win a broader case against Samsung. If they were to win a broad case against Samsung, and believe me some of their claims are ridiculously broad, they would immediately sue every other manufacturer that uses Android.
Edit: This is the OBVIOUS infringement:
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iOS.... vs ..
Touchwiz