tutorial on parser

[John Fabiani]

Hi,
I'm attempting to learn how to convert MsSQl Transact-SQL to postgres pgsql. 
So far my readings have led me to finding a parser. I'm looking for a
tutorial on how to get it done.  I did find a commercial product but they
want over $10,000 us.  This way beyond my means.  Therefore, I need to get
it done either myself to find a open source project.

Thanks in advance.
John Fabiani