Include sometimes?

I’d like to include a flash banner on a php page only sometimes.
Here’s the set-up. I’ve got an admin section for the client to update a part of his site with news, etc. I would like him to be able to check a box or something that will add the banner to that same page. He’s a sports handicapper, so he wants a way to show off that he’s hot (his picks have been winning).
What’s the way to go about this?
Obviously set up a seperate file with just the flash code, and have it as an include(); I’m not sure how to go about this correctly, and I’m very new to php/mySQL. (the site was in place before I began working on it).
If anyone can point me in the right direction.