I have uploaded a mini HOWTO into my techie documents section that covers configuring a Linux machine running Xorg to make best possible use of a Logitech keyboard and mouse (the Elite and MX700 respectively) and the bundles they are sold together in (the Duo MX and Cordless Desktop MX). It requires a fairly recent distro because it uses some features/data only available in Xorg so far. Personally I am using these settings without problems on my Ubuntu Hoary machine. A direct link to the HOWTO is here.