Today, according to a russian website Vista.ru the final version of IE9 have shown Microsoft is already planning ahead, with references to Internet Explorer 10 hidden inside the browser.
The site has uncovered a dialogue box that references IE10, It reads:
Internet Explorer 10 is now available
Get the most from the web. Upgrade from Internet Explorer 9 to Internet Explorer 10 for a fast, clean, and more trusted web browsing experience.
Microsoft appears to be using a placeholder image for the logo until the next version's logo has been decided. Other than that, the dialogue reveals very little else, but it does suggest that Microsoft is planning to give IE its own upgrade system separate from Windows Update.