GPIO on Android

I have some questions with regard to accessing the GPIO via Android.

I) For the 2.1 version of Android on the DVD does this include GPIO access
as part of the kernel?

II) Would I need to recompile the kernel to include GPIO functions?

III) Are there interrupts associated with the GPIO which are accessible
from Java? For example, if a button is pressed will an interrupt be fired,
or would I have to poll the inputs?

IV) Is it possible to designate a GPIO output as PWM, and have it output at
some frequency in a way which is independent of the user interface (i.e.
not slowing it down excessively)?