vSphere 4 is now GA and available for download if you are evaluating it. However if you have Support & Service contract for in-line free upgrade of your licenses, your out of luck (or at least this morning when I tried 3 different ways).
If I went in and said I wanted to evaluate it, then I could download everything just fine.
If I get an email saying vSphere 4 is ready for download I should be able to download it. Am I asking too much?