On t-nation.com there is an article by Coach Davies of Renegade Training that helps a person prepare for the clean, look in the 2004 archives or search under Davies or Power Clean.
Other basics to work on if you are hell bent on learning the clean are bottom squats, front squats, deadlifts, high pulls, overhead presses, and push jerks. I think that without working those exercises, which are good ones overall, someone might not be able to excel in their attempt at a weighted clean & press since those are like the step by step breakdown of a clean & press. Once you get the hang of the clean & press then try "The Bear" complex from an article by Coach Davies.
Now even if you can't around to doing a good clean & press, doing exercises mentioned in the above paragraph are just as good. I forget what strength coach said this- doing squats and deadlifts takes shorter time to learn than cleans, and those will increase your cleans, but cleans won't increase your squats and deadlifts.
Ah personal learning advice on the clean & press, I spent a month using a broomstick to get the technique down. I don't think there's any shame in that, 'cause it beats being all messed up.