Also of interest are the Major Pentatonic scales (blues players will use them sometimes - Jimi Hendrix comes to mind): Basically take any major scale and take out the 4th and 7th notes. Or 12356. Example: C major would be CDEGA. Repeat ad inifinitum. I won't talk about the blues minor scales since they've been talked about, but just one thing to keep in mind - The sharp 4, or flat fifth, that you add into the minor pentatonic to get the blues scale, is also the tritone of the root. So that little fact may help you out.
Bass lines: Probably more complicated than the melody, these bass lines consist of either regular triads, fourths, fifths, or tritones. The 12-bar progression I I I I IV IV I I V IV I V is used often. You can also add in sevenths, chromatics, and octaves for color. Chromaticisms are used A LOT in blues. That sharp 4, or tritone, you hear in the melody is characteristic of the blues scale, but also, blues players will approach notes using chromatics to get an additional blues feel. Honestly, I don't know much theory about the bass when it comes to blues, I know most of what I play by ear. Here's an example:
7-b8-8-1 (Bb-B-C-C)
Another bass line:
1-8-3-10-5-12-7-14-8-15-7-14-5-12-3-10-1-8. (Or think octaves ascending in a seventh chord pattern, up and down the chord)
There's also oom-pah and walking bass, do a search and you'll find out more about these styles (which also have been used in jazz as well).
Other posters have listed some excellent artists to listen to regarding the blues - this will help you the most, IMO.
I'm still learning blues myself, there's a lot to learn, but you should get a lot of mileage from the stuff that's been posted. Listen and learn. One of the key things about blues is improvisation. The blues is the one place where you can improvise in one key, on the same chord progression, until the cows come home.
Btw, the fingering for the scales can usually be reduced to 12312 and repeat for the minor and major pentatonics. For blues scale itself, try 123412 and repeat.