I have the Droid 1, rooted with Ultimate Droid Froyo. You can put any app on the SD card with that ROM (not sure if all Froyo builds can). However I ran into an issue moving Facebook and Twitter to the SD card. The widgets removed from the home screen and they weren't showing up in the widget list anymore. I moved the apps back to the phone and rebooted to fix. Not sure if just a reboot alone would have fixed it if I left them on the card.