Watch the Freting the Strings online guitar lesson by David Hamburger from Blues Guitar For Beginners
Yes, it's true - most of the great bluesmen of the past probably didn't read written notation or talk about their music in terms of sharps and flats or whole notes and half notes. And ultimately you're going to have to learn the most important nuances of how to play the same way they did - by watching other people play and listening closely to records of your favorite musicians. Meanwhile, it won't hurt to soak up a little book learnin'.
>>How To Read Sheet Music