Can you please suggest some books to get how guitar effects: distortion, overdrive, phaser and so on are achieved ?
DAFX is a pretty good one.
Harmony Central used to have a surprisingly good knowledgeable base for algorithms but that seem to have disappeared since Guitar Center took them over.
A lot of source code can be found at http://www.musicdsp.org/, but it's fairly varied in quality.
If you want something a bit more simple than the Dafx book then I recommend this dissertation that i stumbled across a while back. Even if you have no idea how to use simulink, the diagrams might help you understand how the various guitar effects are realized.