KVM Switch
 

Does anyone use one to switch between a Mac and PC? Recommendations? If its possible do you use a PC or Mac keyboard? Do you need to remap the keys?

Right now of have 2 monitors, 2 keyboards, 2 mice. Its kinda of a pain switching back and forth.

Leopard has a feature to switch the command, option, and control keys. By default, the Windows key is Command, and the ALT key is Option. This is the reverse of the Mac keyboard's physical layout, so you can switch them if you prefer your PC keyboard.
I would recommend an Iogear KVM. IOGEAR - KVM & KVMP Solution

1. Does anyone use one to switch between a Mac and PC?
I Have a KVM not quite what you are doing but similar.

2. If it’s possible do you use a PC or Mac keyboard?
Yes, No issue what so ever.
Ctrl (PC) = Control (Mac)
Start (PC) = Command (Apple Key - Mac)
Alt (PC) = Option / Alt (Mac)

It does get a bit of use with keyboard shortcuts, but as Edward mentioned it is possible to tell OS X to remap the keys

My only concern is that if you unplug a monitor in OS X is that it changes the display settings. I'm not sure if this will affect you but I have been using duel screen and accidently turned off a screen and dropped a frame while capturing (SUCK!)... Maybe ask a mac specialist....?

Good luck, I'm sure it can be done no problems, sure beats wondering every time you use your mouse why it’s not working.....

Most Iogear KVMs act as a monitor itself, so even when switched to computer B, computer A still thinks it has a monitor attached, and won't search for one.

How is the switching between them?

I currently have an Intellinet 4 port switch, but when I switch back to my PC (Vista), it always takes about a minute before it recognizes my keyboard and mouse. The Mac Pro sees them right away.

The Iogear models seem to be a bit pricey too.