Read about this in a issue of WIRED. Apparently a, or a group of, hacker(s) took out Estonia's network and technological resources after the Estonian officials voted for the movement of statue built in rememberance of the end of Russian war on Estonia or something. Well, they were told by the Russians that if they moved it, they would pay. They moved it anyway, and three days later the attacks began.

so it was the russians.. i thought so. estonia had blamed them for the attacks, but they of course denied it