Register Add Post at the Same Time

I recently moved a long running site from MT to WordPress 2.0 (I finally have a unified set of software across my sites!) but in the process I set up the site to require that people register in order to post. Since that point posts have been nonexistant. Does anyone know of a way (plugin or hack) to prompt someone to fill out all of the fields for both a registration and a new post on the same page? This would eliminate several extra steps for the user which would make a huge difference in participation.

I can probably hack it, but would like to avoid modifying the core and would hate to reinvent the wheel.

Thanks!