Jon Udell’s justly-praised Library Lookup bookmarklets snag the url of a book you’re admiring on Amazon.com (or BN.com, or other book site), and finds out if it’s in stock at your local library.
You can find the Austin link on this page. On Firefox/Windows, you can “right-click” to bookmark the link, and add it to your Personal Toolbar folder.
The only thing it doesn’t do is return the books for you.
I’ve got a version of LibraryLookup for the UT-Austin libraries – http://www.ischool.utexas.edu/~donturn/utnetcat-liblook.html
Enjoy!