Yes, you can format it from within Windows, but it has to already be partitioned. Just use your Windows cd, and play along like you're gonna install Windows on that drive, and then don't go through with it. Just create the partition, then reboot, and format it from within Windows.
edit: There's a big, long, drawn out way of partitioning it from Windows, but as long as your copy of Windows is legal, it's much easier not to try to explain it.