I created a little Windows Script file that you can put in the root of a site that when double-clicked will run IIS Express without its usual accompanying console window.
IIS Express seems to require a parent process so you have to keep the calling process alive whilst it's running. The lowest tech way I could think of doing this is to use Windows Script Host's WScript.Run method that allows you to spawn processes in a hidden window and wait for them to exit.
You can view and download the code here. https://gist.github.com/864322
Just place the IISExpress.js in the root of your website and double-click, it should then launch your browser at the root of the site. You can adjust the port and CLR version by tweaking the variables at the top of the script.
Hope it helps!