Hi Alan,
There isn't a good solution for this. Since each page is a new request, you can't use a UpdatePanel to solve this issue. For IE, you can use this proprietary solution:
http://imar.spaanjaars.com/314/smoot...ge-transitions (Note: old article, so I don't know if this still works).
Other alternatives include "single page applications" that don't make full page requests but instead load data dynamically. However, SPAs are a huge subject of their own, bringing in many, many new concepts and technologies.
Cheers,
Imar