Get it from Software Update.
The Apple Remote Desktop Client version 1.2.4 update delivers improvements to security, performance, and reliability of the Apple Remote Desktop 1.2 client software running on Mac OS X versions 10.1, 10.2 and 10.3. For more information on this update, please refer to http://www.info.apple.com/kbnum/n107670
The Apple Remote Desktop Client version 1.2.4 update delivers improvements to security, performance, and reliability of the Apple Remote Desktop 1.2 client software running on Mac OS X versions 10.1, 10.2 and 10.3. For more information on this update, please refer to http://www.info.apple.com/kbnum/n107670