We prove that if G is SL_2(F) or PSL_2(F), where F is a finite field, and A
is a set of generators of G, then either |AAA| > |A|^(1+epsilon), where epsilon
is an absolute positive real number, or AAA=G.

As a corollary we get that the diameter of any Cayley graph of G is
Poly-Logarithmic in |G|.