1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 6.Be3 Bg7 7.f3 0-0 8.Qd2 Nc6
1.e4 c5
The Sicilian Defense has the reputation of being black's most aggressive response to 1.e4. With 1...c5, black immediately discourages white from playing 2.d4 because black would be able to capture the pawn. In response, white would be reluctant to recapture with the queen because the queen would be extremely vulnerable in the center of the board.
In order to pursue the center, white must instead prepare d2-d4 with 2.Nf3. When white continues with d4, black will capture and white will be able to recapture with the Nf3 rather than the queen.
Black can pursue many different strategies in the Sicilian, but nearly all have one thing in common. Black will usually try to take advantage of the open c-file by placing one or more rooks and sometimes the queen there. Very often, therefore, black will castle on the kingside and pursue an attack on the queenside. By contrast, in part because the black king is on the kingside, white will attack there.
The following "variations" may provide you with a sense of the complexity of the Sicilian. Try to get a feel for the patterns of development.
The Dragon:
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 6.Be3 Bg7 7.f3 0-0 8.Qd2 Nc6
The Velimirovic Attack:
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 Nc6 6.Bc4 e6 7.Be3 Be7 8.Qe2 0-0 9.0-0-0 Qc7 10.Bb3 a6
The Najdorf:
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bg5 e6 7.f4 Be7 8.Qf3 Qc7 9.0-0-0 Nbd7 10.g4 b5
Sources for further reading
J.Edwards, THE SICILIAN: AN OVERVIEW, R&D Publishing, 1993
D.Levy, HOW TO PLAY THE SICILIAN DEFENCE, David McKay, 1978
J.Nunn and J.Gallagher, BEATING THE SICILIAN, Henry Holt, 1995