Has anyone tried reading a sim card from the arduino? can this be done? i saw ladyada's sim card reader but i need something to work with the arduino? I'm planning to use it for kind of data storage - like a cheap smart card.
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
the reason is simple.. I'm looking at a cheap storage medium for very simple data storage - kind of identification data. Given the fact that mobile phones have invaded the earth, sim card is the most easily available form of storage to anyone. Also i see a trend where mobile companies are throwing them at consumers for free hoping they woud make money later 
so was hoping to try and use it in a simple fashion.
Reading code is out of question right now (i'm still a starter for that kind of work)
ok from what i understand about sim cards (and i might be wrong here but this is what I understand from reading varius sites), is that it is easy to delete messages, modify teh address book, etc. (all phone features). However, to do anything else, i.e - add your own new data it gets very complicated and it involves unlocking the phone etc.
If you are looking for identification using phones why not use bluetooth, almost all phones come with this feature now. Plus the user doesn't havent to take the sim card out of his phone all the time.
Also not all phone companies use sim cards. Bell and Telus in Canada, which account for approx 50% of cell phone users, here use CDMA and most phones don't have sim cards
I can use bluetooth but i thought what if there are 10 different bluetooth devices around? pairing might become a headache 
and if i'm using it for identification things might get a bit complex.
i didnt think of that. isn't there a way to make your arduino accept many connections and then you just filter out the ones you dont want an keep the ones you do want.
i remember the "Making things Talk" book had a lot of bluetooth examples. I'll take a look at that when I get home