Customising pro-sites checkout

Hi,

Pro-sites checkout page lists the levels and prices but there (appears) to be no way of adding a short description of the features of each level.

Is there an easy way / standard way of customising? Have I missed an option somewhere? It seems a bit much to present people option at checkout would some form of product description or a link back to a product description.

Of course I could modify the checkout code, or use javascript to add some element to the page, but would like your thoughts before commencing any hacking.