You ask a very relevant question, right now there are probably several million people who feel the same way. It does not make sense that they all should work independent of each other, so I am sure there are organizations that have already started this process. If I do a search with ogpile.com for impeach Obama:
you could contact the Tea Party or World Net Daily (WND) or others to get official forms. Then you could find 1 to 4 hours a week to go door to door and be engaged.