Samsung Spring Preview
The D407 appears to be a replacement for the D357. Both are clamshell GSM phones with Push-To-Talk and Bluetooth for Cingular. Although we didn't have the opportunity to compare them side-by-side, the D407 seemed significantly smaller and lighter than the D357. Otherwise the phones are mostly similar, including monochrome outer displays and speaker-independent voice control. The D407 does add streaming video playback (presumably for MobiTV).
The D407 also adds a VGA camera, although a non-camera version - the D347 - will also be available.