This post has been moved to http://blog.cumps.be/visual-studio-2008-and-php-coloring/ where you can find more information. (with screenshots!)
Visual Studio is a great editor! But when editing other file formats I miss the coloring.
I'm a PHP coder as well (coming from the fact that I don't like Classic ASP) and I use VS.NET for editing my PHP files as well. And guess what, that's another file format, so no coloring. But I want it, badly.
So, here's the solution:
Download this .zip file, and extract it somewhere.
Run the registry file that matches your VS.NET editor. (The only difference is the 7.0 to 7.1 from 2002 to 2003).
Now copy usertype.dat to your VS.NET directory (default: C:\Program Files\Microsoft Visual Studio .NET\Common7\IDE).
If VS.NET is running, close it and restart.
Now just open a .php file, and admire the coloring. And the '+' signs to collapse functions also work as a nice extra!