Plug in the compact receiver when you're ready to work, then snap it into your mouse when you travel, saving hassle and battery life. Easily enlarge and edit details with the new Magnifier and scroll four ways with the innovative 4-Way Scrolling.
Microsoft Wireless Notebook Optical Mouse 4000 | Mouse | RF | USB wireless receiver | Optical | Buttons Qty 4 | Movement Resolution 1000 dpi | Scrolling wheel, High Definition Optical Technology | Battery: 1 x AA type
Microsoft Windows 2000, Microsoft Windows XP Home Edition, Microsoft Windows XP Professional, Microsoft Windows XP Tablet PC Edition, Microsoft Windows XP Media Center Edition, Apple MacOS X 10.2 - 10.3 | Package Type OEM
Cheapest I've found this by far, FREE shipping too (I purchased as a business user, I don't know if it will be any more/less as a home user). £24.99 on Play.com for a retail-boxed version - OEM is similar to a trade no-frills version (same product though).
This is a great mouse and you will benefit from it to no end.