Document generation from XML

Good evening list, I apologise profusely if after reading anyone thinks that is OT, but I relally need some pointers with a project I am working on. I have searched the Internet for information on XML document generation but there is too much information that I cannot decide which way to go. Thanks lots in advance. I am currently writing a web based application using PHP that created reports on the fly from a multitude of data sources. In the beginning only one output format was required, HTML and then PDF was a requirement. More and more formats are now required by my users and rather than create a new output script for each different format I am thinking about outputting the final report as XML and then putting that through 'something' to render in the format that I require. However I am unclear as to the best way to do this as there seems to be many different ways. I have looked at using Apache FOP and DocBook, but they all spawn off in different directions and bringing in other things such as Jade. This post maybe slightly OT, but if nayone has any pointers on how I amy go about doing this I would be very very grateful. Thanks very much. Russell