How to handle XML

I’m building an Amazon store in WP. I’ve figured out how to generate signed URLs for Amazon’s API, but the response I get is xml. I need to figure out how to parse and display the relevant information in the xml.

To see an example of what I currently get, go to http://www.donkata.com/?page_id=129

What options do I have to handle this output? My searches thus far have proved fruitless.