Hitting, slapping, kicking, head-banging toddlers
No fear ME2, we have been going through the same phase with our daughter. Hubby has taught her to high five instead of hitting or slapping us. It works most of the time;except of course tonight. He swears it only took a few days to teach her. We've also tried time-outs, but I really don't think they work (other than getting the child away from you and out of his/her hitting range). Plus I'm a little worried that she'll start associating her bedroom with punishment and that will backfire on us when we move her from the family bed. Anyway....
You might want to start here: Dr Sears' discipline index. This section explains how the drive for independence causes some unpleasant behaviors. This section gives some helpful tools for modifying behaviors (I've found the "gentle" touch or "one finger" touch somewhat effective). Here's the section specifically on biting and hitting.
I also try to figure out what caused the problem: often she is sleepy or hungry. IF that is the case, I deal with it appropriately. Other times, she's just being aggressive. When that happens, I just set her down, tell her hitting is wrong and walk away. It feels cruel, especially when she cries hysterically after me, but I think it will help her see (eventually) that hitting another being is wrong. Or I am psychologically damaging her for life.
I like this explanation: "Kids do annoying things ? not maliciously, but because they don't think like adults. ***Remember that what she is doing is developmentally appropriate. She's exploring and learning. "
Hang in there ME2!