Check out this excellent write up on Typophile on how to setup a flexible baseline grid in Adobe InDesign. The author has set up the grid so that every baseline is 12pts apart. This is a good setting that gives you a few leading options to choose from, but someone commented below the article that they’ve setup a 3pt system, which in my opinion works very nicely. Having a baseline every 3 pts gives you great flexibility with leading allowing you to create typography that is more dynamic.