JimS and Cameron bring up two great points......you need to know what you want out of lessons.
I knew that I had problems with my fundamentals. I had video taped myself taking some shots. I then put the video on youtube and post a thread here.....asking for instructors (and others) to evaluate my fundamentals. Even though most all comments on my stance, bridge and stroke were all constructive, but I didn't really understand how exactly I should go about changing them. Point is, there is no replacement for one-on-one/group instruction. All the posts and instructional video tapes/dvds can't replace what I learned from seeing a professional instructor.
As for the record and not to take anything away from Randy, I actually narrowed my search down to the closest instructor and researched their creditials (sp?). I could have easily choose either pooltchr or Scott Lee and would have if they were closer than Randy.
In the future I would like to attend Randy's expert course and possibly seek out another instructor that specializes in the game itself.
Mattman