I used it, IIRC, when it was first released for the Mac (it's multi-platform) and it was easy enough. All the virtual machine software is basically the same at the most basic level. It's really just installing it (Sun Virtual Box, VMWare Fusion, Parallels Desktop), then doing a File > New (or similar) and walking through a wizard. You can download a trial of Windows 7, totally legal BTW, and install without an activation key.
Windows 7 Digital River direct links: English, Spanish, German, French; X86 & X64
That post contains links to many different localizations of Windows 7, again totally legal. Just follow the instructions to have a genuine trial.