Shane Nackerud writes: "FreeReserves [1] makes your e-reserves site database driven, and some of its best features include a simple copyright management feature, password protection, security at the document level, and the ability to handle multiple filetypes. FreeReserves is a free program; you can redistribute it and/ormodify it under the terms of the GNU General Public License." Looks like several different institutions are already using it, too...
Links:
[1] http://www.lib.umn.edu/san/freereserves