Go to Tools and select Manage Add-ons.
Then select Search providers.
You'll see Microsoft Live Search and whichever options you chose during install. If that was Live Search, that's all you'll see.
Now click Find more search providers.
You'll get a list of various options. Press "Add to Internet Explorer" to add the providers you want. Each time you'll get the option to make it a default search provider, and include terms in the suggested search terms. If you don't see your favorite. Scroll to the bottom and click "Create your own search provider."
Now open a new tab, and enter the URL of the search engine you want to include. Search for the word TEST in all capital letters. Copy the URL of the search results page by highlighting it and pressing the "Windows" and "C" keys at the same time.
Now click back to the tab that says "crate your own search provider." Use the "Windows" and "V" keys to paste the URL you copied earlier into the box marked URL. Then give the search engine a name. And press Install Search Provider. If you want to make this your default search provider, check that box. Then press Add one more time.
Now when you type a keyword in the search box, icons for all the search engines you selected will show up. Just click on one with your mouse to search the keywords you typed in that engine.