@ Cymric
You won`t belive it, but it is quite straight forward.
Just go to the official Lego site
www.lego.com and select Customerservice -> Building Instructions
http://www.lego.com/eng/buildinginstructions/I don`t know if older model are available, but will be able to download plans for the entire programm just on sale. As nearly every set has some special parts in it, the plans alone are quite useless. so there is no need to keep then secret.
What I am looking for is as site where I can download Lego productcatalogs back to about 1980 to refresh childhood memmories.