there are several possibilities.
To contribute directly to the recounts, you can contribute to the individual candidates' campaigns (be sure to mark it FOR RECOUNT so it doesn't go to help settle any campaign debts, etc.),
OR you can also contribute to Help America Recount, the 527 set up by DUer hedda_foil (and IdaBriggs, I think was involved), the two DUers who got this whole recount ball rolling in the first place. Hedda is co-founder also of the National Ballot Integrity Project. The two links are below:
www.helpamericarecount.org
www.ballotintegrity.org/
Some background for the above info:
*****Want to Help America Recount? The website is UP!
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=132x1344801Link: www.helpamericarecount.org
National Ballot Integrity Project
http://www.ballotintegrity.org/***** Donations for the Recount" Fundraising Kit > > >
(Use this to send to your friends -- enormous amount of info -- pick and choose what you need)
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=203x37833BACKGROUND:DU INFO ALERT: Why Recounting in New Hampshire Could Save Democracy
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=104x2617155Need Some DU Help w/New Hampshire Stuff!!! (URGENT)
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=203&topic_id=26802&mesg_id=26802RALPH NADER MAY SAVE THE WORLD!!! (Its NOT Over in NH!) Updated Fri 8:15p
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=203x25116Nader requests NH vote recount. (Did we just make a huge blunder?)
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=102&topic_id=965216Nader, Cobb and Badnarik may all be willing to look into recounts in Ohio
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=203x26843