jTDS - Open Source Type 4 JDBC Driver for SQL Server
If your looking for a JDBC driver for SQL Server that will work on multiple platforms, and is free - take a look at jTDS. The jTDS project also claims that it is the fastest JDBC driver for SQL Server, based on these benchmarks. Though the benchmarks doesn't include the DataDirect Drivers that ColdFusion MX is bundled with, nor the JTurbo driver that BlueDragon is bundled with.
I have been using this driver for about a year now in a standalone batch java utility I wrote, and I have not had any problems connecting to SQL Server 7 or 2000 with the driver.
From the site:
jTDS is an open source 100% pure Java (type 4) JDBC 3.0 driver for Microsoft SQL Server (6.5, 7, 2000 and 2005) and Sybase (10, 11, 12). jTDS is based on the work of the FreeTDS project and is currently the fastest complete JDBC driver for SQL Server and Sybase. Starting with release 0.9 jTDS is 100% JDBC 3.0 compatible, supporting forward-only and scrollable/updateable ResultSets, multiple concurrent (completely independent) Statements per Connection and implementing all of the DatabaseMetaData and ResultSetMetaData methods. Check out the feature matrix for more details.
Quite a few of the commercial JDBC drivers out there are based on jTDS (or FreeTDS), even if they no longer acknowledge this. jTDS has been tested with virtually all of the available JDBC-based database management tools and is the driver of choice for most of these (it is distributed with Aqua Data Studio and DataDino as the driver for SQL Server). jTDS is also becoming a common choice for enterprise-level applications: starting with release 0.8-rc1 jTDS passes the Hibernate test suite, making it the driver of choice for SQL Server.