You are correct that Microsoft doesn't distribute an HSQLDB driver. It is the responsibility of the database vendor to distribute ODBC/JDBC drivers or OLE DB providers for use with their database software.
I see on the HSQLDB web site (http://hsqldb.org/web/hsqlDevelopment.html) that ODBC driver development is in the works but it doesn't seem to be active since the last SVN
version of the ODBC files are nearly 2 years old. I'm guessing the open source development team is concentrating their efforts on the database engine rather than connectivity from languages other than Java. They are apparently looking
for volunteers to help with ODBC so feel free to jump in.
Dan Guzman, SQL Server MVP, http://weblogs.sqlteam.com/dang/
