Well, technically, "informational" is correct. Informative is also valid. Informational more specifically meaning "having the nature of information", such as the site itself being a form/source of information. Informative would more specifically be viewing the site as an external entity simply providing information, and not actually being information itself.
It's a tough call, depending on whether the site is viewed as a "document" of information, instead of a provider of information. hehehe. Ahhh... the subtlety of semantics. As for the final comma, that is also correct. In fact, the last comma of such a list is a more formal syntax, and in many cases necessary to avoid confusion with grouping within a list (especially one where the list is group with an "or" instead of an "and"). While not having the comma is generally valid, many will always include it as it can never be wrong to have it, but CAN be confusing or misrepresenting of the intended statement in some cases if omitted.