Hi,
my son really started hitting a lot at 15 mos--but really slapping me in the face, it was so disrespectful--i used "Raising a Happy, Unspoiled Child" ( out of print, find on eBay), and it helped a lot, but my son was younger. at that age the discipline was just ending the contact "we were aving fun, you hit me, i am leaving you in your room for 1 minute until you apoligize". it worked between us.
I was able to curb my son's hitting with me, but then as he got older he hit his grandma and he BIT HIS DAD! My hub had to wear long sleeve shirts all summer because of the marks. One night, my hub said "look at me, I am in an abusive relationship" and it was true--he was covered in bruises. he asked and asked and asked around, and for the biting he was told to pinch my son right when he bit him. We were psycho-no-physical punishment people--and it worked for me and my son, but my son was just physically abusive to his dad--and dad had to pinch 2X--we haven't had a bite in weeks.
Also, I don't think my son is a bad kid for being soooooo physical. i just think he's par for the course for boys.