Nokia phones with Symbian S60 3rd ed. feature pack 2 can display contacts from your phone memory and your SIM card at the same time, but on phones with feature pack 1 (or without feature pack) you have to dig deep down in the options menu to see your SIM contacts.

Or you can install the Python application SIM directory. This simple piece of code which floats all over the Symbian forums puts an icon on your phone for direct access to your SIM contacts. .

this requires python installed