I've done some research on my own and it sounds like you might not want to include alkaline batteries in your collection. Here is a link to an article that tells why...
http://willtaft.com/136/there-may-be...line-batteries.
I could not find one organization that would not charge to accept alkaline batteries. It wouldn't be good for you to collect them and then have to throw them in the trash, since that would be misrepresenting your efforts.
Good luck with your collection! I think that anything positive that is done to reduce our own personal impact on the earth is a great thing!