[drupal-devel] AJAX selects, with images--and documentation

I'm working on a module that need AJAX-populated selects with images. An example might be: user selects from a list of his/her posts. A second select is then populated with a list of users who have commented on that post, including their images. Anyone working on this sort of functionality? Existing examples? More generally, in core we've got a great start and some good examples to work from. It would be great to pull this together so we've got tutorials on how to leverage and expand on the AJAX approaches. Is there documentation on implementing AJAX in Drupal modules? If not, any volunteers? Thanks, Nedjo