If the Google Toolbar isn't enough for you, now you can try the Google Deskbar. Like the Toolbar, it requires Internet Explorer, but unlike the Toolbar, it allows you to do Internet searching without opening your browser. The Deskbar can be downloaded at
http://toolbar.google.com/deskbar
When you install it, you'll notice that it installs on your Windows taskbar. You can either search Google directly or use the little black down icon to change the search to another of Google's properties -- Froogle, Google News, Groups, Images, etc. There are also options to go to non-Google search properties like Rotten Tomatoes and Download.com (Google's options include the ability to add your own custom search sites.) Google mentions a few use ideas on their download page, but I found the ability to quickly lookup phone numbers the best feature of this deskbar. Or you can use it to resolve math equations with Google's calculator. You can also type define:GDP and google will tell you what does it mean (Gross Domestic Production) For additional information on the Deskbar, visit the Deskbar FAQ at
http://toolbar.google.com/deskbar/help/faq.html
or participate in the (quite busy) forum at
http://groups.google.com/groups?hl=en&group=google.public.labs.google-deskbar

Please Note:
System Requirements: Windows 98/ME/2000/XP and Internet Explorer 5.5 or higher.
Click on Help - About Internet Explorer to check the version. If it's less than 5.5, you can't install Google Deskbar.