Thanks to Alan B. for this tip: You can make Bing your default search provider in Internet Explorer 7 or 8 by visiting Microsoft's Create Your Own Search Provider page and entering the following information:

URL: http://www.bing.com/search?q=TEST

Name: Bing

Then, click Install Search Provider. (And be sure to check the box to make it your default provider.) You'll even get the Bing logo in the search box. Nice!