For ordinary phones (NOT Blackberry, or Windows Mobile 5 & 6), like your typical Nokia, Motorola or Sony Ericsson etc., the mobile requirements are a phone that has bluetooth and runs Java applications (with CLDC 1.1 minimum) AND it has to comply to JSR-82.  See additional FAQ: How will I know whether it will work on my mobile phone? In summary:

For JavaMobile version (all non-Blackberry, non-Windows Mobile devices:

• JSR-82 compliant
• CLDC 1.1 or higher

Use the GS911Verifier.jar to test compatibility (see related FAQ)

If you don't know whether your phone complies to the above, please look it up, Google it's specifications or contact your Mobile phone vendor - do not ask us!

For BlackBerry:

• it has to have Bluetooth ;-)
• You can also run the JavaMobile version on a BlackBerry (that run smartphone software 4.2.1 or newer) - The BlackBerry then has to comply to the JavaMobile requirements above)

For Windows Mobile devices

• a WinMobile 5.x or 6.x or 7.x device with Bluetooth

All other devices

• Have to use the JavaMobile version, hence have to be JSR-82 and CLDC1.1 compliant - use the GS911Verifier.jar to test compatibility (see related FAQ)