If you've been using FrontPage and are ready to embrace the world of standards-based web design with Expression Web, or if you're still unsure and need more convincing, PixelMill has created a helpful series of in-depth articles to help guide you on your way:
http://www.pixelmill.com/support/al1095.htm
Anna
Read the complete post at http://blogs.msdn.com/xweb/archive/2008/04/02/transitioning-from-frontpage-to-expression-web.aspx