Though not specifically about national parks, there's a new web portal out in cyberspace that I thought you not only would enjoy, but find useful. It's called the Encyclopedia of Life.
Why bother pointing it out? Well, much of the information that you can find at this site applies to the national park system. Here, in a nutshell, is what the Encyclopedia of Life is all about:
The Encyclopedia will be an online reference and database on all 1.8 million species currently known to science and will stay current by capturing information on newly discovered and formally described species. The Encyclopedia of Life will help all of us better understand life on our planet
And, for those of you who are good with a camera, or want to report a sighting of a particular species, later this year the Encyclopedia will be open to contributions from the general public.
More importantly, though, this site is rich with information and graphics. It's definitely worth checking out.