When you build on a multi-processor (or multicore) machine the default in VS2005/8 is to build projects in parallel if possible, using one thread per installed logical processor. The output is decorated with a sequence number to distinguish which project it is associated with; output line appear in chronological order.
In VS2008 there is another output window available, "Build Order" in the dropdown list, that sorts by the project number.
You can disable parallel building in Tool / Options / Build-and-run, set the number of parallel threads to 1.
