Parse XML data into WordPress MySQL database as custom fields

I have an XML job feed which I would like to integrate with my website which is running on a WordPress platform. I have a good understanding of WordPress and am familiar with it's database schema.

The XML job feed is delivered automatically via FTP to my websites server via a zipped archive file which contains an XML file with the data updates/inserts/deletes as well as any associated images.

The process should be as follows:

1. Check if there is an archive file
2. Unpack the zip file
3. Move images to the appropriate location
4. Parse the XML file data
5. Delete files once processed

The WordPress schema is very simple and so any data which does not fall into the WordPress post title or description would be stored as custom fields.

I am looking for a php script/library which will assist with the parsing of the XML data into the My开发者_StackOverflow社区SQL WP DB. This is an area which is very new to me so I would appreciate all advice on this matter.

If you're familiar with jQuery, see phpquery - might make your life easier. One person's HTML is another person's XML.