Yeah. He confirmed it on the Opie and Anthony Show last week. I just did a search, and Wikipedia has this:

On September 3, 2008, Foley's agency, the Gillespie Agency, issued a press release that stated Foley had signed a short-term deal with Total Nonstop Action Wrestling (TNA). Foley claimed in the statement to be "very excited about the specifics of this agreement and the potential it holds". On September 4, on Foley's official My Space profile, Foley posted a blog which ended with, "See you in the Impact Zone". Foley made his TNA debut on September 5, at a TNA houseshow in hometown of Long Island by giving a short speech about how he loved the product