The theory element of it is easy, as it is mainly based around a 6 note scale, which is just a standard pentatonic scale with a note added. Although, blues music does not just use these scales, artists use a diverse range.
As for doing something creative and emotive with the blues, that is something you cannot just learn. It is something you aquire. Playing blues can be harder than some of the stuff people like Steve Vai do, because it requires emotion, feeling, creativity, imagination and honesty.
Try listening to some Rory Gallagher, Stevie Ray Vaughan, Buddy Guy, Robert Johnson and Muddy Waters for some great examples of this.
As for websites about the blues I would recommend typing into Google 'blues scale' and 'how to play blues' and find some stuff which suits you. Also, try the website http://www.ultimate-guitar.com/ for some handy tips and a great online community.
Hope this helps.