Access posts via AJAX or IFRAME

I’m using WordPress as the “online help” engine for a web application I’m working on. I’d like to find a way to make the online help more integrated with the actual application by loading some of the help content from inside the application. What I’m looking for is a formula for getting just the content (no skin or widgets) of a post or page out of WordPress.

Some approaches I’m thinking would work are:
– Write a magic PHP file that loads the wordpress libraries and dumps raw post/page contents (does something like this exist already?)
– Use the XMLRPC interface; however, I can’t find any good docs on this, unless WordPress really supports the GData API now used by Blogger.
– Discover a magic query parameter I can add to a URL that changes or disables the skin on any page (this would be perfect!)

I’m pretty new to WordPress hacking so I thought I’d see if anyone would be nice enough to save me a ton of research time with a few good pointers.

Thanks in advance,
Dobes