thanks to Brian Kerr for showing me this; Ann Arbor specific; I don't have a screen shot to show you.
The iPhone's Safari web browser has a good RSS viewer inside it, which will display a feed nicely as a web page so that you can make your way through it.
As a result, the private RSS feed that the Ann Arbor District Library provides for holds and checkouts - or the public feeds for searches - show up nicely. Brian notes that the books that are available now show up first on the list when you display it.
When I go to my favorite iPhone simulator it doesn't simulate the feed reader support, so I don't have a screen shot here.
one more reason to support RSS