Assuming you have been using Virtualbox before, then the upgrade process to Virtualbox 3 is going to be easy and smooth sailing.
For first time users of Virtualbox or in fact virtualisation who are using a Mac OSx then you should read my earlier posts on how to get going. These are:
How to install Virtualbox on a Mac using Windows TinyXP
So what next - let me know what you are using Virtualbox for.
Tags:Read more from my blog for an introduction and quick tips on developing in Hugo or UCTD.