XML Newbie. HELP!

Hi! Ok, this is not a question about PHP, but since this is such a great discussion forum, I am certain it is a good place to get started with a new technology. The thing is I have a DTD specification and I want to translate it into a DB schema, and then create an "add-delete-modify" application. OK!! It might seem I am asking too much, but I don´t even know if this can be done, so any comments will appreciated. It would be great if you just gave me a link to a good XML and DTD tutorial. I also want to know if I can create XML documents with PHP, what kind of software do i need to parse those documents, and how can I put the data in my DB. Any clue, and I mean ANY, will be appreciated. THANKS A LOT IN ADVANCE! Cheers, Diego.