I came across a good post that discusses a few places you can go to find the information for stopping junk mail.  It mentions ForestEthics, OptOutPreScreen (two thumbs up by Federal Trade Commission), and MyJunkTree.

Usually, to stop companies from mailing you junk catalogs and mail, you’d have to do the research and write them opt-out letters.  In addition, these requests must be renewed/refiled once every 5 years.  The federal law allows companies to start mailing you again after 5 years is up.

When you think about the time involved, the stamps you need to lick, and the letters you must write and deliver, you might find that using one of those paid services is not so bad after all.  MyJunkTree offers a 3 year subscription for $20 (is that per year or per 3 years?).

With an online postal mailbox and paperless billing, my belief is that your normal mail and junk mail will be reduced by 90% or more.  However, your primary residence still receives mail right?  Services like MyJunkTree will likely help you out on this front.