XML, Parser and newbie links

Hi, recently I was given the task to create an application to generate xml files in order to exchange data. Since my knowleadge of xml is close to zero :) I also received an english text explaining the DTD and an example of how the file should be written. So I got to a point where I simply should create a php script to access my databases and output the data in the requested format, right ? Well close but not quite. I am supposed to parse the file with the DTD in order to validade it. This seems to be the place where I got lost. So how exactly (with php or perhaps another tool) can do this ? Thanks. PS. If possible send me some urls with a tutorial of XML so my next questions wont be so basic ;) __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/