Backtrack has dbpwaudit in /pentest/database/dbpwaudit, however, it does not come with the java jar files required. So, first you have to go download them. The easiest way I found out to do that is by simply searching for the aliases and then googling them. You can get the aliases with the -L option:
user@HOST:/pentest/database/dbpwaudit$ ./dbpwaudit.sh -L
DBPwAudit v0.8 by Patrik Karlsson <patrik@cqure.net>
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Oracle - oracle.jdbc.driver.OracleDriver
MySQL - com.mysql.jdbc.Driver
MSSql - com.microsoft.sqlserver.jdbc.SQLServerDriver
DB2 - com.ibm.db2.jcc.DB2Driver