Plug-In(s) for Captioning a Slideshow

I am an administrator of the website http://saint-albans.org. We have a slideshow that appears on the front page of the website and we would like to add captions to those images, similar to the captions that appear in the slideshow on the homepage of http://www.stdave.org. Is there a captioning plugin for WordPress that allows you to enter the URLs of existing slideshow images in a field and a corresponding caption in another field? Failing that, is there a plugin which allows you to easily caption existing slideshow images? I’ve tried various plugins, but right now, I’m stumped. Thanks for any help!