The Heck reaction is a very popular palladium catalyzed reaction. There is a ton of primary literature out there.
A good books to look at would be "Palladium in Heterocyclic Chemistry" by Jack Li and Gordon Gribble (Pergamon, 2000) and "Transition Metals in the Synthesis of Complex Organic Molecules" by Louis Hegedus (University Science Books, 1999). Both books discuss the mechanism.
Here are some primary references as well:
Heck, Acc. Chem. Res.
12, 146 (1979)
Overman, Pure Appl. Chem.
66, 2323 (1994)
Negishi, J. Am. Chem. Soc.
112, 8590 (1990)
Perhaps Mitch could put up the mechanism on our name reactions page.