As others have said the meaning is near identical, however I would add one idea in relation to context.
I think 'help' is very general and can be used in all situations, while 'help out' has a couple of ideas attached to it (for me at least) one is that you will not be helping alone. You may be helping me, or another person, or even a team of volunteers etc.
Can you help me with this problem? (May imply: Can you do it for me)
Can you help me out with this problem? (Probably implies lets fix it together)
These are only my perceptions and so they are my personal differences in usage and understanding. And in reality in either situation they are completely interchangeable!!!!