Depending upon a number of things -- size (how many) and complexity (how organized) -- you may want to take a look at
DSpace (
http://dspace.org).
It's kind of aimed at institutions (libraries, museums, academic) but, if your collection is huge, it's perfectly usable. There is a learning curve (not too steep) and you will need to install some software; e.g., Apache Tomcat and others, but installation and configuration is straight-forward and well documented.
Take a look at the web site and see if it might fit your needs.
Hope this helps some.
