I use LinuxMint 12 in VirtualBox on my MBP for non-work projects. I think that OS X is an excellent environment for software development but I am also mighty pleased with LinuxMint. I use a VM for non-work projects just to make sure that everything stays very separate. I decided today that I'll never get used to where the Control key is so I went looking for a way to swap the fn and Control keys. I saw a couple separate sites reviewing KeyRemap4MacBook so I decided to try it even though most forums said that you can't remap the fn key.
I use Lion so I downloaded version 7.5.0 for Lion. The zip file drops a pkg. I installed that and got a System Preference added to my system. (I did have to reboot.) The new preference is KeyRemap4MacBook: at the center of the bottom row.
I opened the widget and was immediately dazzled! Fn to Control_L (only in virtual machine, RDC) I enabled that, fired up VirtualBox (I'm using v4.1.6), and booted my VM.
I could hardly wait to try it...