To call swing districts: Call.BarackObama.com. That will automatically give you a targeted list of voters in a swing district.
To volunteer with MoveON with a campaign near your home, go here: www.moveon.org/2010
If you want to call from home, go here: pol.moveon.org/2010
If you want to go to a MoveOn campaign event, go here: pol.moveon.org/event/lastchance