Until recently, we had a "New Books" feature on our site that sorted out 
new books by LC classification (in addition to some other views).  I 
have attached a ZIP file containing:

1) An HTML file documenting the structure of the database table that it 
pulled our new book data from;

2) The PHP to load a subject area, using the first letter of the LC call 
number as a broad category.

It's not especially sophisticated, and it basically reiterates the 
broadest LC classifications, which may not make a whole lot of sense to 
some end users.  But perhaps you'll find it useful as a starting point.  
This one takes the letter from a parameter in the GET request, but you 
could easily get the call number from a database query and slice the 
first character off.

I'd love to show you a live copy, but unfortunately the New Books 
feature got decommissioned a couple weeks ago on the grounds that it 
took too much staff time to separate out new acquisitions.  They are now 
sent directly to the stacks with no markers in the catalog to 
differentiate them from any other book, so the corresponding web stuff 
was removed.

Will Martin

Web Services Librarian
Chester Fritz Library
University of North Dakota