This is not what was stated by Somasager stated, here is what he said:
However, we will not support Visual Studio .NET 2002 or Visual Studio .NET 2003 as development environments on Windows Vista.
That statement just points out that Microsoft will not be "supporting" VS 2002 or 2003 on Windows Vista. That is not to say that those products "won't run" on Windows Vista. What it does say is that if it does work on Windows Vista and there are any problems, Microsoft will not be addressing said problems.
I've spoken to a few people who are running Visual Studio 2003 on Windows Vista and for the development that they are doing they are experiencing no problems. I did come by this document, which is kind of funny since Somasager stated that "we will not support" yet the document is on a Microsoft site... anyway, take a look at it and if you aren't doing any of the items on that list, it'll probably work just fine for you. If you are, most of them have work arounds (or fixes due to configuration changes) so you'll still have a good chance that, at least with Visual Studio 2003, that it'll work.