ODBC stands for 'Open DataBase Connectivity' is a popular standard for accessing information from various databases from different vendors. Applications written using the ODBC drivers are guaranteed to work with various databases like PostgreSQL, Oracle, Sybase, Informix etc..
There is an interesting project called the FreeODBC Pack Package . There's no PostgreSQL Version there, maybe you can help.
UDBC is a static version of ODBC independent of driver managers and DLL support, used to embed database connectivity support directly into applications.
JDBC stands for 'Java DataBase Connectivity'. Java is a platform independent programming language developed by Sun Microsystems. Java programmers are encouraged to write database applications using the JDBC to facilitate portability across databases like PostgreSQL, Oracle, informix, etc. If you write Java applications you can get JDBC drivers for PostgreSQL from the following sites:
JDBC driver is already included in the PostgreSQL distribution.
Java programmers can find these classes for PostgreSQL very useful.