Just any old GSM compatible SIM card (bonus for 3G USIM).
I presume I need some hardware? Can anyone recommend something cheap for hobbyist, and something more professional?
I presume that there will be full docs of an API with the h/w, so maybe this should be tagged "no-programming-related"? Sorry, if so.
Any good URLs or books (I am conversant with the 3GPP standards).
I'm not (black hat) hacking, don't worry, just not pleased with the likes of SIM Card Secretary, Data Doctor Recovery, etc, so would like to code my own, but might turn it commercial, or offer SIM card programming services (data recover from damaged card, etc) as a sideline.
Update: while I am primarily interested just reading my SMS for backup, it might be a bonus if someone knows of a cheap SIM card writer (so that I can back up all or part of the SIM and restore it later)
You can do that with any PC/SC smart card reader (and writer, as others pointed out) and a program that can read and parse the data for you.
Direct answers to your questions:
I am one of the people from the team that created SIM Manager and the aforementioned SDK.