Microsoft Frontpage is being replaced with Microsoft Office SharePoint Web Designer 2007 and Microsoft Expression Web Designer - both of them are based on Microsoft FrontPage but serve different audiences.
Old Wine in New Skins - Paul Thurrott remarks that Microsoft Office SharePoint Designer 2007 is virtually identical to Microsoft Frontpage. Old Wine in New Skins
Microsoft SharePoint Web Designer vs Microsoft Expression Web Designer
Microsoft Expression is more for professional Web designers building standards-based sites, while Microsoft SharePoint is aimed more at typical cubicle dwellers looking to post information on internal Web sites and automate business processes.
Microsoft Frontpage Rise and Doom
Microsoft acquired FrontPage in the mid-90s, virtually killed Adobe PageMill and other WYSIWYG HTML tools before being dethroned by Adobe GoLive and Macromedia Dreamweaver.