oh yeah, forgot to tell ya that if you get a direct hit (meaning the visitor types the url directly into the window themselevs) then it will be blank space from where they came from. so you prolly better off with something like this:
var referred_from=(document.referrer=="")?referred_from="a new window":referred_from=document.referrer;
document.write("You have came from "+referred_from+" and you are using "+navigator.appName+" "+navigator.appVersion);
the first one that says "a new window" is what will show up if they are a direct hit.