Hi Merry,
Our museums use Collective Access, a free, open-source software for cataloguing and publishing museum and archival collections. We are using it as part of a collective, so we have more support than if we were on our own, but it works very well, and has a public facing component as well, if you'd like to put your collections (or just some) online. It is web-based, so I can access it from anywhere.
www.collectiveaccess.org
The consortium we are part of is called ConnecticutCollections, if you'd like to see the public portal.
Connecticut Collections
Good luck,
Jodi