Is the Nexus One battery charged when connected to a PC via USB? Do you happen to know whether the Nexus One's battery is charged while being connected via the USB cable to a PC?

If so, is this standard behavior for all Android devices that have a USB port?
I don't know about the N1 in particular, but as far as I know, most (if not all) phones charge via USB so long as the USB port provides enough power.  My Motorola Droid and G1 charge via USB. My Nook Color and Motorola Xoom (tablets) do not charge via USB.

However, do note that it is faster to charge with the phone plugged in to a power source instead of a USB port.