Given the fact Sunnis and Shia are at each others throats in a way we have never seen I wouldn't say the insurgency is done. Zarqawi is as close to success and as close to failure as he has ever been and the same goes for Iraq as a whole. We are at a pinnicale point in time, the jihadists are increasing to their greatest level ever the killing of both Sunnis and Shia to push them toward over the edge into civil war. The next several months until the election are going to be some of the hardest, not for the US military, but for Iraqis. If the Sunnis vote and get representitives in government in December the insurgency is done. ol'Zarq can do all the killing he wants, but the Sunni community as a whole would turn against all the foreign fighters at that point.
This Summer will be mostly training Iraqi security forces and keeping civil war from breaking out. However, this fall and winter will be what destorys almost all support for the insurgency with the Constitution and the election.
And btw...there won't be a civil war.