Same thing here. He's 3 now and its not quite as bad. Not sure what to do about the talking back.. Drives me crazy..

Recently, I took my sons fav toy away for the rest of the day for hitting and yelling. So far so good..

Have you tried asking to use his words? I know my daughter was going through a similar phase. My husband and I went right to correcting her behavior and saw that she only became more aggressive as time went on (i.e. instead of throwing herself on the ground, she started hitting us).

The approach that worked for us was asking her to express how she felt, why and how mommy could fix it. I get down to her level, ask her to stop (maybe even hold her arms and tell her we're going to use our words now ok?. This is not okay. You don't hit because it is an owie to mommy. Tell mommy what's wrong so we can try and fix it. Mommy is here to help you. Are you upset because you want to keep on playing and mommy asked you to come inside?" Make suggestions as to what's making him unhappy, to encourage him to #1 use his words as opposed to his actions #2 to let him feel like he's being heard and validated #3 to encourage him to use words when there's conflicts in the future as oppose to actions. Let him know that mommy understands that you're upset because you want to play but mommy said 5 more minutes and 5 more minutes are all done. Can you show mommy how you say bye to the park?
Praising when he shows you the proper behavior is a big thing as well.

Good luck :)

I am also having this same problem with my 2 yr old. He just turned 2 when he started this. To me it's extremely innoying. I've tried explaining using his words to tell me whats wrong, but that's when he talks back and usually yells it at me. I've tried sticking him in the time out chair where he has no toys. There's got to be something out there that we can do for a more positive kid proof way to keep our sanity in stadge in our kids life. :)

My three year old does the same thing, its defiantly a stage they go threw, they have great advice on babycenter.com about things like that, its all age appropriate things u can do for disiplne, what i would suggest, is reward for good behavior...I mean my daughter has a fun bucks system, for every week she picks up her toys she get a dollar, they are fake, or helps make dinner by throwing things into a bowl or stiring , shes get 2 dollars, if u reward good behavior they tend to look forward to the end product like a toy at the end of the month or a trip to the dollar store...for bad behavior we take fun bucks away, so with our system either way shes learning bad behavior has consicuenses, as does good behavior.