Below, there are links to volunteer in 12 competitive Senate races. (Poblano at the NYT ranked these races as either toss-up or leaning).
Also, there's a facebook (FB) link, in case you want to "like" the candidate.
Incumbent Senators are indicated by their title.
Also, you may want to check for Obama campaign offices, in case there's a coordinated campaign.
Peace out.
FLORIDA
Sen. Bill Nelson (D) versus Connie Mack (R)
Sign-up to get involved (General sign-up with optional comments). FB.
INDIANA - Sen. Lugar (R) tea-bagged in primary
Joe Donnelly (D) versus Richard Mourdock (R)
Sign-up to volunteer (Pick specific tasks). FB
NEW MEXICO - Sen. Bingaman (D) retiring
Martin Heinrich (D) versus Health Wilson (R)
Sign-up to volunteer (Pick specific tasks). Apply for an internship in Albuquerque. FB
MASSACHUSETTS
Elizabeth Warren (D) versus Sen. Scott Brown (R)
She has a great website. Make calls. Write a LTE.Sign-up to volunteer. Sign-up to canvass. Find an event. FB.
MISSOURI
Sen. Claire McCaskill (D) versus Sarah Steelman (R)
Sign-up to volunteer (Pick specific tasks and include a note).
Visit a local campaign office. FB.
MONTANTA
Sen. Jon Tester (D) versus Denny Rehburg
Sign-up to volunteer (Indicate availability: days of the week and time). Sign-up to join the message team (online action). FB
NEBRASKA - Sen. Nelson (D) retiring
Bob Kerry (D) versus Deb Fischer (R)
Sign-up to volunteer (Pick specific tasks). FB.
NEVADA
Shelley Berkley (D) versus Sen. Dean Heller (R)
Sign-up to volunteer (General sign-up form. You can pick issues of interest). FB.
NORTH DAKOTA - Sen. Kent Conrad (D) retiring
Heidi Heitkamp (D) versus Rick Berg (R)
Sign-up to volunteer (Pick specific tasks). FB.
OHIO
Sen. Sherrod Brown (D) versus Josh "Empty Suit" Mandel (R)
Sign-up to volunteer (Pick specific tasks). FB
VIRGINIA - Sen. Jim Webb (D) retiring
Tim Kaine (D) versus George Allen (R)
Make calls. Sign-up to volunteer (Optional comments section). FB.
WISCONSIN - Sen. Herb Kohl (D) retiring
Tammy Baldwin (D) versus ? (R primary on Aug 14)
Sign-up (General form). FB.