hmm.. this seems interesting. Any reason in particular you are trying to interface with a sim? if you are just planing simple data storage you might be better off trying to interface an SD card, espeacially since a lot of work has been done on them already.
I can't seem to find any info on arduino+sim combinations done already. The only way I can think of attacking this is reading the pySim source code and trying to port it to the arduino