FreeTDS is a set of libraries that allows programs to natively talk
to Microsoft SQL Server and Sybase databases.

Technically speaking, FreeTDS is an open source implementation of the
TDS (Tabular Data Stream) protocol used by these databases for their
own clients.  It supports many different flavors of the protocol and
three APIs -- DB-Lib, CT-Lib, and ODBC -- to access it.

Homepage:
http://www.freetds.org/
