Greasemonkey for IE is an Internet Explorer extension which lets you to add bits of DHTML ("user scripts") to any web page to change its behavior. In much the same way that user CSS lets you take control of a web page's style, user scripts let you easily control any aspect of a web page's design or interaction.
Customize Google for IE (CG4IE) is an Internet Explorer extension that enhances Google search results by adding extra information (like links to Yahoo, Ask Jeeves, MSN etc) and giving the user more power over Google interface and security settings.
Customize Google for IE is an open source project inspired by and based on the CustomizeGoolgle Firefox extension.