I put a 'pop up' basket/bin thing into my young son's bedroom fairly early on so that he got into the habit of putting washing in there, gradually progressing on to taking it into the bathroom himself. My rules are that if the stuff isn't in the washing basket then it doesn't get washed. My little guy is better than my big guy at picking up after himself, there lies another problem!!!
We tell our kids they don't need to worry about picking up after themselves, and that we're happy to do it. BUT (and this is a big "but") they're well aware that if WE pick something up--toys, clothes, shoes--we have the option of giving it away or throwing it out. This generally keeps them in line and picking up after themselves.
It only took me once to get the hang of picking up after myself.. When I was around six years old, my mom sent me out of the house for the day, and cleaned my room for me. Anything that wasn't in it's place, she threw out. Needless to say, from that day on my room has been clean.
Do like that mother in the USA - she told her family they got three warnings from her to pick up their stuff, if the three warnings were issued and the items not put away - she put them up for sale on Ebay! Apparently she did go through with it and put her sons playstation up for !