I wash the leaves really well. I dry them really well. I place about 15 on a paper towel and I put another on top of that. I put them in the microwave for about 1 minute, 25 seconds and then I take them out and they are dry. They seem not to lose too much of the smell but they do get a little darker in color.

Also, I haven't tried this yet, but I heard on Cooking Live on the TV Food NEtwork that if you place basil leaves between layers of coarse salt in a jar, that they keep indefinitely without losing color or fragrance.

Hope this helps.