Here is a wonderful tip I learned at my cooking class from Chef Katie http://cookologyonline.com/
The next time you really want buttermilk pancakes and do not have buttermilk on hand do not FRET. You can mix 1 cup of milk (skim, 1%, 2% or whole) with 1 tablespoon of vinegar. Let sit for about 10 minutes and VOILA! Buttermilk. No need to buy expensive buttermilk EVER again! Time to celebrate!