I just got access to the beta today and have been playing with the app. It looks great, and it's really impressive what you can do as a web-based app.
One feature that I couldn't find in the Settings was the ability to change which phones my Google Voice number forwards to -- not the Call Back number, but the destinations of incoming calls. The mobile version of the Google Voice web site allows you to change this setting and I use it constantly to change where I want to receive my calls (office extensions, home, work blackberry, etc). Unfortunately using the preset calendar doesn't work for me.
Am I just missing where this is? If not, could you add that in as a feature request?
Thanks!!