popup-ing a window

[??????]

hi,

where can I put this code

<SCRIPT TYPE="text/javascript">
<!--
var answer = confirm ("hello, you are not a member, do u want to register?")
if (answer)
window.open("http://www.mywebsite.com/vb/register.php?action=signup")
else
alert ("have fun")
// -->
</SCRIPT>

and what templates to modify so that when someone visits my website, a messagebox is shown as above.

[nemesis]

thank you but you sticks script in which template?

[Admin]

Both of you, please go to this page and enter your username, to show you are licensed. (you will need to use your customer number and password to access that page)
Thank you.