A short but interesting program at the 2007 Alaska Library Association annual conference was a brief demo of the Bering Strait School District (BSSD)'s Koha based Intergrated Library System ILS. The public catalog is available online.
Presenter Darla Grediagin (email@example.com) said that using Koha, an open source library catalog, had dropped her annual ILS maintainance fees from $5,000 to $300. Plus, she feels that she has much better tech support. The catalog, the admin and circulation modules all looked great and responsive.
You can see what Darla went through to get her catalog up and running by visiting her Alaska Bush Library Service blog and clicking on the "koha" link in the right hand column.
As far as anyone knows, BSSD is only one of two school library installations in North America. Darla would love to have more company and encourages people to contact her about Koha.