Check out
http://www.goldstar-sw.com/btrvodbc.asp.
It's a good primer on accessing Btrieve files using ODBC. Basic overview of things you'll need:
1. DDFs. The DDFs describe the Btrieve files. They are not DSC files.
2. ODBC driver. PSQL 7 had a seperate ODBC driver install. Newer versions have ODBC included with the client install.
Once you've got an ODBC DSN, you can import or link the tables using Access or any ODBC compliant app.