I am enjoying the copy of Visual Studio Team System: Better Software Development for Agile Teams by Will Stott and James Newkirk that I picked up the other day. So far, it is doing a good job of both explaining Agile and how an Agile team might use VSTS. They've even gone to the trouble of creating a VSTS process template for XP. Of particular interest to me, though, in light of my recent post, is this bit on IID:
... software is developed in a series of cycles which each deliver some working software (iteration) that builds upon what has gone before (incremental).
Short & sweet - just like I like it!