there are lots of makes, belkin is probably the best known, but you will find it cheaper to get a 2 port belkin omnicube kvm switch on ebay and only connect the monitors, but you could easily share the keyboard and mouse as well.
they usually sell for £20.00 or so. You may need 2 additional monitor cables (pc to kvm switch)for about £5.00 each, a bit more if you want ps2 as well to share k and m as well.
image quality remains perfect and i have 2 x 4 port kvm switches with 8 pcs and then split to two separate k v and m's with a reverse kvm setup.
image is still perfect on CRT and TFT.