Yes, a press release came across yesterday afternoon that Fiat and Chrysler have signed a "non-binding agreement" for Fiat to have a 35% interest in Chrysler. It goes on to say that no cash is involved, only access for C to F's technology.
Allen R
On Edit: Sorry, forgot about your question re: GM and Fiat. In 2005 (I think) GM paid a bunch of money to walk away from a deal with Fiat. I don't think GM got back in to the company later.