from the developers guide:
Connecting to an application on a SIM card
For BlackBerry® devices that operate on EDGE networks, you can create BlackBerry Java® Applications that use the APDU and JCRMI APIs defined by JSR 177, to call the methods of an application on a SIM card. You must use the BlackBerry® Java® Development Environment Version 4.2.1 or greater to create a BlackBerry Java Application that uses the APDU and JCRMI APIs.
The APDU API enables BlackBerry Java Applications on a BlackBerry device to use the APDU protocol to communicate with an application on a SIM card.
The JCRMI API enables BlackBerry Java Applications on a BlackBerry device to use the Java Card Remote Method Invocation protocol to communicate with a BlackBerry Java Application on a SIM card.
For more information on creating BlackBerry Java Applications that support JSR177, see The Java Community Process(SM) Program