"headinclude" Template Question

I want to insert pop-up banner code into my header, but I ONLY want it to be there if the user is a guest (so that registered users will not receive pop-ups). In other words, I want to stick a template name like $bannercode in my headinclude template, so that the code will be inserted if the user a guest, but will not be inserted if the user is logged in. What do I need to do to accomplish this?

[Xenon]

install logicians template condition hack

[LanciaStratos]

Oh, wow, yes that does look like it will do the trick! Thanks!