I don't believe it was an inside job. Way too much evidence to support that 9/11 happened the way it was reported, angry muslims hijacked and flew planes into the twin towers and the Pentagon and were forced to crash a fourth plane in Penn. by a passenger revolt. A member of my family witnessed the plane fly into the Pentagon.
Now, whether the government knew more about what might happen and allowed it to happen anyway, I can't say for sure. I like to believe that they were just inept and it is most likely what happened, since it seems someone credible would have came out by now and said that the WH/government should have known w/ X, Y, and Z as evidence. However, I know that the other way is a possibility.