Vermont Deadline: you must be registered to vote by 5 p.m. on the Wednesday preceding the date of the election.
In another state:
Alternatively (recommended), go to the website of the state agency that handles elections in your state. Access state election websites from the U.S. Election Assistance Commission. Most states have in-depth information on their website about how to register, the deadlines for registering, and have the official state form that can be downloaded/printed out and mailed in. Remember that you will probably need to request an absentee ballot as well.
Deadlines: The U.S. Election Assistance Commission maintains a calendar of state registration deadlines.
Caution: some states have much earlier deadlines than Vermont.
Resources for Voter Registration:
Vote411.org (sponsored by the League of Women Voters)
Rock the Vote
Elections & Voting page (National Association of Secretaries of State)