In a recent thread, I mentioned I'd solved part of my space/storage 
problem by building a rolling rack for my lumber. Enough people asked in 
private where the plans were that I thought it was worth posting the 
answer publicly for those that meant to ask but never did. :-)

The plans are on page 32 of the April 97 issue of American Woodworker 
(this is the issue with Ian Kirby on the cover chopping a 
mortise...showing the simplified bench he has an article about).

The rack is part of the "Tech Tips" section so don't expect a full blown 
article here. Also, the way they show it, there's no "floor" in the 
rack...put a piece of scrap 3/4" plywood across the bottom so you can 
stack short/small stuff in there. Otherwise, you're wasting a LOT of 
potential space/storage.

It's a simple to make thing and most dimensions just aren't that 
critical. You might want to use a 2x6 along the back edge (where sheet 
goods get stacked) since a 2x4 is pretty narrow (can't stack much and it 
doesn't lean enough to keep it in place easily...a 2x6 along the bottom 
would probably work better.

Enjoy,
Tim S.