Android Contacts lost but seen in Message app
In the contacts app, press menu, then there should be some sort of option for display - this lets you change which contacts are displayed. At the minute you're probably just displaying your gmail contacts, but you should see the setting in there to display Sim contacts. My advice would be to copy them to gmail, you should find some sort of export/import tool in your contacts app too - just export all contacts from your Sim to a file on your phone, then import that file and select your gmail contact book, that means your contacts will always be available