Seems that the all so fabulous Froyo of ours is limiting us on setting our phone on silent via volume rocker. I confirmed with a friend that had recently upgraded to 2.2 to test out his rocker settings. Just to find that 2.1 does let you set to silent, but not anymore on 2.2. So options for this will be menu>setting>sound>vibrate. Now the other option is holding down the power button and setting the phone to silent.