In Internet Explorer 7, there is a new Search box next to the Address box which you can make a search without going to the search engine's page.

The default search engine is Live or Bing by Microsoft. Here I have changed it to Google Search as my default. When I type in a keyword/term in the search box, and press the ENTER or the Search button, search result by the default search engine will come up on the current tab

If you click on the drop-down of the Search button, holding ALT key and click your mouse on a search engine, IE would open a new tab to do the search.

You can add more search providers as illustrated in the following 3 images.