When there’s a will, there’s a jailbreak app! It’s called SIManager and it will help you move your contacts from iPhone to SIM.
SIManager is available on Cydia for free from the iSpazio repo. Simply download the app and launch it to get started…
To import your contacts from your iPhone to your SIM card, hit the little settings icon at the bottom, then hit “Copy iPhone to SIM”. All the contacts you have on your iPhone will be backed up to your SIM card.
Now if you want to move these contacts that are on your SIM to your iPhone, go to Settings > Mail, Contacts, Calendars > Import SIM Contacts. All the contacts that are on your SIM card will be transferred to your iPhone.
Most importantly this app is free, so Enjoy!