Title says it all, but basically, will I be able to use my iPhone 4 MicroSim [with fullsize SIM card adapter I assume] in another unlocked cellphone like those cheap no-plan phones at like Walmart? Whenever I go out exercising, hiking, playing ball, etc. I like to have my phone on me, but I feel uncomfortable whenever I bring my iPhone 4 on those rough-and-tumble activities. So, as a compromise, I was thinking about getting a really cheap phone with some basic functions (texting mainly, though having a music player would be welcome too) that I wouldn't mind if it got knocked about some accidentally. Speaking of, does anyone have any suggestions for a cheap (under $40 total, including tax/s&h) phone like that? Also, if I got a new substitute phone that was able to browse the internet, would my current iPhone data plan cover it? Can I use the iPhone 4 MicroSim in a non-3G phone in general? Also, do any brick and mortar stores sell those fullsize SIM adapters or would I have to look online for one? Thanks for the help!