Indiana
http://www.in.gov/sos/elections/Indiana has absentee in person voting and absentee mail-in voting. In Indiana anyone can vote early.
Voting Window: October 6th-November 3rd (in person) or now- November 3rd
Florida
http://election.dos.state.fl.us/Florida has early voting and mail-in voting. In Florida anyone can vote early.
Voting Window: October 20th-November 1stst (in person) or now- Nov 4th (vote by mail)
Missouri
http://www.sos.mo.gov/elections/s_default.asp?id=votingMissouri has absentee voting by mail and in person. In order to be able to vote absentee, one must fulfill one of various criteria such as: Absence on Election Day from the jurisdiction of the election authority in which such voter is registered to vote (due to, say, volunteering).
Voting Window: In person now-Nov. 3rd. Absentee ballot requests by mail must be received by October 30th.
Montana
http://sos.mt.gov/elb/index.aspIn Montana absentee voting = early voting. Anyone can vote absentee.
Voting Window: absentee in-person now-September 25th by-mail now-November 3rd
*I am little perplexed by the voting window here, and would suggest you call the free voting hotline to confirm the dates 1-888-884-VOTE (8683)
New Hampshire
http://www.sos.nh.gov/electionsnew.htmlNew Hampshire has absentee voting. You must qualify to be able to vote absentee, by (for example) being out of the county on election day volunteering.
Voting Window: October 3rd -November 3rd.
New Jersey
http://www.njelections.org/New Jersey has absentee voting in-person and by-mail for any voter.
Voting Window: now-November 3rd
New Mexico
http://www.sos.state.nm.us/sos-elections.htmlNew Mexico has early voting and absentee voting available to all voters.
Voting Window: Early voting October 6th-November 1st. Absentee voting now-Nov 4th
New York
http://www.elections.state.ny.us/New York has absentee voting in-person and by mail. You must qualify to vote absentee in New York, by (for example) being "unavoidably absent from your county on Election Day" while volunteering.
Voting Window: In person October 5th – November 3rd.
Ohio
http://www.sos.state.oh.us/SOS/voter.aspxOhio has absentee in-person and by-mail voting available to all voters.
Voting Window: September 30th – November 3rd.
Pennsylvania
http://www.dos.state.pa.us/bcel/site/default.aspPennsylvania has absentee by mail. You must qualify to vote absentee in Pennsylvania, by (for example) "expecting to be absent election day" while volunteering. I was not able to determine if there is absentee voting in person.
Voting Window: now – November 3rd.
Virgina:
www.sbe.virginia.gov/cms/Index.html
Virginia has in-person and by-mail absentee voting. You must qualify to vote absentee, by (for example) "being absent from the county or city" due to volunteering.
Voting Window: September 20th-November 1st
Washington
http://www.secstate.wa.gov/elections/In Washington any registered voter may vote early by mail.
Voting Window: October 15th to November 4th
Wisconsin
http://elections.state.wi.us/Wisconsin has in-person and by-mail absentee voting. Any registered voter may request an absentee ballot.
Voting window: now-November 3rd.
from HOW TO Vote Early - A State-by-State Guide
This was posted on Daily Kos by zorland.
http://www.dailykos.com/story/2008/9/10/164040/562/998/593949