A Problem I Encounter with White's e Pawn in the Sicilian


The downside of the fianchetto is that it takes two moves. It may be more effective to charge into the center in the first move with pawns or knights.
Try some of the variations of the Sicilian listed on this page:
http://en.wikipedia.org/wiki/Sicilian_Defence
The bottom line in any opening is control of the center and quick and effective development.
I cannot figure out what to do with my knight when white advances the e pawn to threaten it. This has happened to me a number of times with a number of different setups. Here's a diagram:
What should I do?