To add a provider to the Internet Explorer 7 Instant Search box, click on the down arrow (next to the glass) at the Search box & click on "Find More Providers". Select one of the Web Search or Topic Search provider's to add them to the list, you can add custom Search provider's in the Create Your Own section on the right.
You can switch the provider by clicking on the down arrow at the Search box -> select the provider that you want to use. The provider's are saved in the registry, I've exported some of my favorites, just merge them + restart Internet Explorer and they are added to the list.
The zip file below contains the following SearchScopes:
• deviantART - All, Digital Art, Icons, Photography, Skins & Themes + Wallpapers (find that lost wallpaper smile.gif)
• Event ID (Enter an Event ID number to get the description)
• Google & Google Image Search
• IMDb Search (Movie Database)
• Ixquick Metasearch & Ixquick Picturesearch
• MetaCrawler
• MSDN Enhanced Search
• Neowin Forums biggrin.gif
• SourceForge.net
• Wikipedia
• YouTube