Facebook Fanpage with 900k likes

Have you tried CPA offers? Find a CPA offer that allows social traffic and link your fans to that.
If you page is for a specific niche, try posting amazon items.

Just a couple of thoughts.

Cheers I will look into that

How active is your page?

With all the easy ways to buy facebook likes, the number of likes is meaningless unless they are real people who are active and interact with the page.

If the page does have ACTIVE members, then I would suggest finding the biggest problem that may have or perceive that they have and either find an affiliate product to promote to them, or create a product that solved there problem and promote that.

However, I would send them to an opt in page from facebook and build a list because people rarely buy on the first contact.

Then, make sure you keep providing something of value to both your fan page AND you list on a very consistent basis, not nothing and then a lot and nothing and then a lot. Consistency is key to build up a pattern with the people.

If the page IS NOT very active, then start working on getting real active people interested in what the page is about by doing the things I stated above and writing other posts on blogs and such with a button to like you on facebook and then promote that.

That is a huge page. Do not spam it otherwise FB will delete it. Use this page to promote other Pages of yours and Monetize those Pages.

Look at it as a traffic source.

For what could you use traffic?

Taking your niche into account, think about it a little until some nice ideas surface.

Use offers to monetize the fans. Try to make sure the offers are at least somewhat related to what the page represents. And also don't overdue the offers and make it look more natural rather than like a sales pitch or your fans will start dropping faster than you can attract them.

I would have thought that with this much traffic potential there is more I can do than just CPA stuff?

I would suggest to sell it =)