It's a beta, but it works pretty good.  Let me know what problems you run into.

Download the file SQLConverter.exe. 

To use it, you just give it the name of a file containing SQL statements.  Output is written to stdout, so if you want to save the output, you must redirect it.  For example:

       SQLConverter --from oracle --to teradata mysqlscript.sql > myconvertedsql.sql

--from sqldialect
--to sqldialect
-d debug (testing the parsing)
-v verbose output. includes the original SQL in the output.

the sqldialect can be any of:
oracle
ansi  (or ansi-std)
db2
teradata
informix
sybase
mssql  (or mssqlserver)
postgresql  (or postgres)
greenplum  (or gpdb)
redbrick
netezza
mysql

The program was originally for converting to/from Teradata, and has been updated a lot to support Greenplum Database as output, so those probably works best.

the --to dialect  generally only works for a limited set of these, I'll add more as I can.