You can probably pre-order Windows 7, just like you could with Snow Leopard.
I think VirtualBox is free, so you could download that and try it, but it is shareware / freeware, so it's not as user-firendly to set-up (or as someone said above, not as idiot-proof). VMWare, Parallels, and BootCamp are "proper" products by professional companies.![]()
VirtualBox is as "proper" as the others. VirtualBox is not shareware or freeware, it is an open source project.
And to another poster above, VirtualBox is a virtualization program, just like VMWare and Parallels. In other words, yes you install Windows (or any other OS) on it.