'Input Director', and 'Xpize'

Input Director

Input Director is a Windows application that lets you control multiple Windows systems using the keyboard/mouse attached to one computer. It is designed for folks who have two (or more) computers set up at home and find themselves regularly sliding from one system to the other. With Input Director, you can share a single keyboard/mouse across a set of systems. You switch which system receives the input either by hotkey or by moving the cursor so that it transitions from one screen to the other (in a very similar fashion to a multi-monitor setup). Input Director also supports a "shared" clipboard, in which you can copy data onto the clipboard on one system, transition across to another and paste. Input Director requires Windows 2000 (Service Pack 4), Windows XP (Service Pack 2) or Windows Vista. The systems must be networked.

http://www.inputdirector.com/

Xpize

XPize is a GUI enhancer that replaces most of the non-XP icons, avis and bmps that Microsoft has always overlooked. It also includes some extras and a reloader, which you can use after visiting Windows Update.

http://www.xpize.net/?page=home