How to upgrade 3.0 to 4.0?

Hi, I've read through VMWare's documentation, and al lI can find it pre-requiste checkers, compatibility, and features. But I'm looking for a "step-by-step" guide.

I have one host that's 3.0 and all my other hosts are 4.0. I've moved all VM's off the 3.0 host and put it into Maintenance mode. So now what? Do I load the ESX 4.0 CD into it and boot? Can I use the Update Manager instead? Should I just do a clean install?

Thanks!