All U++ help and doc is in files with T++ format (.tpp). They are edited in TheIDE. There are also functions to convert T++ pages into html or pdf.
As Mirek says, using this, uppweb is an application that is run everyday to get the U++ web page from all U++ docs plus svn. You can run it in your computer to get the updated web. Open obtained index.html and it link it to all in your pc.
About the book, now UltimateBook (100% based in uppweb), generates a +1000 pages pdf with all U++ doc.
With a little effort the chapters could be well ordered and taking care of page formating, all book would have the same look.
An additional thing is that the T++ links (to internet or to other T++ docs) remain when converted to html, but they disappear when converting to pdf. It does not seem difficult to solve this.