Am Pentatonic Licks by Peter Vogl will teach you how to play over a standard minor blues progression. This free video lesson uses the audio backing track "Am blues", which is track 4, from the Let's Jam! Blues and Rock CD. To solo over this tune let's start with the A minor pentatonic scale. All the notes in this scale will sound great over these chords. The most widely used position is called 1st position because the first note of the scale is an A, the tonic of the scale, and it starts on the 6th string.
Watch the lesson: Quicktime or Flash
This is what the 1st Position A Minor Pentatonic scale looks like. (listen to this scale)

The extended version of this scale looks like this. Notice this scale is extended lower and higher. Try using both of these scales to solo over the Am blues. If you don't know where to start, purchase the Introduction to Blues Guitar course by Peter Vogl. (listen to this scale)

Here is a lick using the Am pentatonic scale. (listen to this lick)

And here is another one. (listen to this lick)

And here is our last lick using the Am Pentatonic Scale. (listen to this lick)

Try these licks or riffs out. Listen to the audio examples and try to imitate the phrasing. Phrasing refers to the way the notes are played, much like the way we speak. Emphasize some notes, slowing down, speeding up, etc. Once you have mastered these licks, make them your own by changing them up slightly.
Classic Blues Licks by Peter Vogl is a Quicktime video lesson that will teach you how to play some famous blues guitar licks. The licks featured in this 20 minute lesson are modeled after similar licks by Stevie Ray Vaughan and B.B. King. By using slides, hammer ons, bends, mutes, octaves and the E Blues Scale you'll learn how to play like a professional blues guitarist. The download features a Quicktime Video and a .pdf containing tablature for all of the scales and licks used in the lesson all in one .zip file. $4.99
Watch a preview: Quicktime or Flash