If you've already taught hime to tidy toys into a box then you need to use the same principles to teach him to put laundry into a washing machine - if he's already ahppy pickking up objects it really shouldn't be that hard. Make sure you break it down into smal sections so that he doesn't get confused and teach him one bit at a time until he is really confident with it till you move on.
a couple of clips from youtube that should give you an ideas but like I say you are just adapting stuff he already knows.
http://www.youtube.com/watch?v=U31V4maVjg8http://www.youtube.com/watch?v=-Dqd4YgZL0kThis ones fab - I expect the deep drawer was used to prevent the little lad from keeping taking out the bit he had put back in, so it was an easy way of encouraging him to go back to the basket - very sweet

Here's one I didn't watch all the way through, as was getting a bit frustrated on Honeys behalf

but it is a good example of things not being broken down into small enough steps so the dog wasn't getting rewarded enough and started getting a very confused and frustrated and then faffing and avoiding. There was also far to much waffling from the woman before the dog had a clue what was expected of her which just added to her confusion - get the behaviour understood first and then add the cue for the dog to associate with the action.
http://www.youtube.com/watch?v=qSqeL6uZTK4Hope these help