I just found this excellent essay on 'Who is Tom Bombadil'. Even though I dont agree with some things that he wrote, such as Hobbits are afraid of trees, I beleive it is worth reading. I found alot of points he made very interesting. It made me kindof second guess my theory of who Tom is, and now I am flustered again.
Have fun reading.
http://www.cas.unt.edu/~hargrove/bombadil.html