"Or are you wanting to transform XML using an aspx page" YES
Here is my idea:
1. Have all my XML files in a folder on the server
2. In ASPX have a TOC(or treenode) which when selected calls up the XML file
3. The APSX page grabs the XML file, processes it through XSLT and displays the page in ASP.
I write XML for manuals and books. The XSLT stylesheet would produce a TOC, Chapter, Section etc...
I hope this helps.