I have a question for knowledgeable people. I am on a family plan (as the main user) with a total of 4 lines. In Nov. of 2008, me and my sister both upgraded to the phone of our choosings (me=iphone 3G,her=something garbage). My parents lines haven't been upgraded and are still eligible. Well I've been pondering whether or not I should pursue a 3GS or not as I believe I should be able to upgrade one of my parents lines to 3GS (while I call in to take off the data plan on my iphone 3g) and then...after 30 days...call in to once again take the data plan for the new 3GS off and use the 3GS for myself. The problem is I want to limit the contract extensions. Now when I look at my line, it says I am eligible for upgrades on 4/10 (month/year). However, my sisters line has the full 2 year contract associated with her line. Obviously mine has been shortened. If the same thing happens (a contract that is 1.5 years) when I upgrade to the 3GS...great....if not..then I am stuck for an additional 6 months after my sister's contract expires for her line. Has anyone had something like this happen?