This is so wonderful, I had to share!!
The web site www.Libraryelf.com will keep track of multiple libraries and multiple cards (if your library is in their system) and email notices to you when your books are due, which library, which books, etc. This is such a blessing!!! It is VERY easy to use and has taken all my anxiety out of trying to keep track of all those books myself! Blessings to whoever created that idea!
Go and try!