I have to thank you for this little piece of gold.
This plugin saved me lots of time and frustation.
Had a website for a client with a custom Flash menu and header (and html menu) and it was imperative to use www.site.com or the flash menu wouldn't work for some reason with site.com ...and was a big project a few of the components were incompatible with sh404SEF or any kind of seo tool to redirect and the .htacces file wouldn't let us redirect 301 in the server, everytime we modified the file the whole server just crashed and had to reinstall the backup.
A hell of a nightmare.
I could see myself seating in front of my pc figuring out a way around this problem and came across this plugin... took me 10 seconds to install it and be the happiest guy in planet.

Use it if you need to redirect your site.com to www.site.com install the plugin and once you are in the plugin just type your www.site.com in the host field

Many thanks. =o)