According to World Entertainment News Network (via the IMDb), Alan Alda will be auctioning off the dog tags and army boots he wore in the role of Hawkeye Pierce during his time on M*A*S*H to raise money for the Bob Woodruff Foundation, which supports injured troops. The items will be auctioned as part of the second annual Stand Up for Heroes: A Benefit for the Bob Woodruff Foundation, presented by the New York Comedy Festival and the Bob Woodruff Foundation (read a press release here).
The W.E.N.N. article states that the items will be auctioned off at the charityfolks.org website today (Tuesday, November 4th), but I believe the actual website is charityfolks.com. The page for the Bod Woodruff Foundation can be found here. Alda discussed the boots and dog tags in “Memories of M*A*S*H,” a retrospective originally broadcast in November of 1991:
How much will the items — perhaps not the most famous memorabilia from M*A*S*H but still important and with a personal connection to show’s biggest name — sell for is a question I look forward to having answered.