Shaun,
All my Macs run VMwares Fusion.
30 day free trial of Fusion.
http://www.vmware.com/go/try-fusion-en
If you don't need something fancy and want to go for a test drive you can also use Virtual Box from Oracle.
It's totally free forever. I use it as well.
http://download.virtualbox.org/virtualbox/4.3.18/VirtualBox-4.3.18-96516-OSX.dmg
You can actually import your current PC's hard drive as a virtual drive. You can also create the virtual drive from a Windows recovery partition.
Good little write up,
Convert & Use Your Physical Machine In VMware, VirtualBox & Virtual PC
One of the things that is interesting about Fusion is you can run your PC apps as separate "apps" in the OS X environment. Meaning you don't see any of the Windows GUI, they appear like any other native OS X app.
If you plan to run this on a MacBook you may want to take the money that you would have sent on a new PC and max out the RAM and upgrade to a 7,200 RPM HD.
My current daily carry MacBook Pro has 16 GB of RAM and a 1TB 7,200 RPM drive and there is zero performance hit from virtualization.