How do you remove fungus from wood?

A termite inspector told me that during his inspection in my crawlspace, he found areas where the insulation was down and sweating air condiioning pipes had caused fungus to develop. He said that it costs about $400 to get this removed professionally, but said you can get stuff at a store to remove it yourself. He also indicated that not doing something could lead to severe damage to the wood.

Any suggestions on good and easy-to-use products or other advise would be appreciated.

Thanks