I am interested in developing a Type 4 JDBC Driver for MS-SQL Server. Where can I get further information regarding the TDS protocol in order to write the code?

A search for "TDS" AND "JDBC" at altavista brought up a number of sites dealing with the Tabular DataStream protocol. Probably most other search engines would do the same. Obviously the Microsoft/Sybase sites make sense and you would probably be interested in the FreeTDS site.