Internet Explorer Extension to Open Current Web Page Using a Different Browser 
Recently the folks at
Lifehacker wrote about the
Open With Add-on for Mozilla Firefox, which adds additional menu options to open the current web page using another browser. This Add-on is comes handy if you need to test your web pages out in Internet Explorer, Chrome, Safari, Opera or any other web browser.
Their post provided me the idea to create a similar extension for Internet Explorer.
"Open With" Extension (and Button) for Internet Explorer Mozilla Firefox
1. Download
firefox.zip, unzip and extract the files to a folder.
2. Move the files
firefox.ico and
firefox.htm to the
C:\Windows\Web directory.
3. Double-click
firefox.reg to merge the contents to the registry.
This adds the Open With Firefox button to the Internet Explorer Command Bar.
Google Chrome
To add the Google Chrome button, download
chrome.zip and follow similar steps as above.
Close all Internet Explorer windows and then re-open. If the button isn’t visible by default, you need to customize the Command Bar. To do so, right-click on the empty toolbar area in Internet Explorer, click
Customize, and click
Add or Remove Commands… 
Select Mozilla Firefox / Google Chrome entries from the list and click Add.
In Windows 7 & Windows Vista, selecting the Firefox/Chrome buttons would display a IE Security window indicating that the program (Firefox / Chrome) would open outside of Protected mode. You can enable "Do not show me the warning for this program again" (and click "Allow") if you don’t want to see the dialog box next time onwards.