Well for starters I know the home page. I am guessing that they will want it to be in at least the main category pages, and probably the check out page too.
I know this is vague but my client told me of this idea a few days ago and we haven't discussed in depth exactly "where" we want this to appear. However, I am pretty sure of the ones I mentioned above.
Here is the example code that would go into the HEAD and BODY tags:
http://www.bryanshobbyshop.com/images/SitePal_ex01.jpg
I just need an example of how to structure an {if} statement to implement this on a page or pages in xcart.