Well i have not tired preparing acorns yet. I am waiting for the acorns in my area to get ripe. Apparently every tree is different on the sweetness of the acorns, and it is suggested to sample the different trees looking for the better acorns.

From what I have been reading on the internet that is what you do. It might speed up the leaching if you do a little grinding before you leach them. It should be faster to leach out of smaller bits than whole acorns. Probably be a good idea to sample some to make sure they are all leached out. I think most of the stuff i have read use boiling water, but the cold leach works, just takes longer.

Here is a website that talks about how this lady prepares them, and some recipes.
http://www.backwoodshome.com/articles2/clay79.html

here is a video that explains how to prepare them and some good info on the hot and cold leaching. Also how to get the oil out if you want to use it.
http://www.youtube.com/watch?v=28yYMb_RwBo&NR=1&feature=fvwp

Have a friend who processes acorns of white oak group - bur, white, chestnut, etc. to make acorn bread.
She shells and removes the pellicle(the thin brown skin on the kernel), then chops/grinds them, with water, in her heavy-duty blender, lets the 'soup' settle, pours off the cloudy water, adds fresh water, and repeats the process until the water is clear. At that point most of the tannins are removed. She says that if you wait until the acorns sprout, the tannins are 'fixed' and cannot be removed by simple leaching.
The native tribes of the American Southwest preferred acorns of the red oak species in their area; stored them, dry, in granaries, then pounded them to coarse flour consistency on pounding stones, and leached by pouring water over the flour.
A good instructional text on traditional Indian acorn preparation is "It Will Live Forever" by Bev Ortiz & Julia Parker.
Another good acorn prep & recipe book is "Acorns & Eat 'em" by Suellen Ocean.