On the RIA Development Center website, there's this recent post showing off the Expression Web 2 software and how PHP developers could use it in their coding work.

Some of the most important new features in Microsoft's recently released Expression Web 2 involve enhanced support for PHP. Don't think this is just a half hearted effort to appeal to the Open Source web development crowd. Expression Web 2 supports PHP developers with a carefully constructed, feature full treatment which you should seriously consider for your PHP applications.

These new features include a built-in development server with integrated browser support, include and design view integration, IntelliSense (code completion) and support for XHTML syntax and syntax highlighting.