Passing current URL via query string

[Mark]

I'm putting an email a friend engine together. I have the form and
mail processing working, but i can't figure out how to pass the
current URL.

The email a friend app will be called using a Light Window, so i need
to pass the current URL to the form via the link.

I honestly don't know where to start with this, so any help would be
great.

Cheers.
Mark