XML Data push

I'm looking into doing something like the following: [best viewed w/fixed width font] User Request User Interface | ^ \/ | Receiving Page --> XML Data push --> Processing Page where the "Receiving page" is a controller and pushes data (as XML) to a processing page. What I'm not sure of is how I can push the data. I'd rather not use sessions and the data would be too large to pass as a get. I've looked at CURL but unless I'm missing something, I'm not sure that's what I need. I'm curious if someone can point me in the right direction? I don't need to know _exactly_ how to do this. In fact, I'd rather figure it out on my own. But as I'm not even sure where to start looking, coming up with that answer is much more difficult. So if any of you know where I can start looking to learn how I can do this, I'd be ever so appreciative! thnx, Chris