License for PostgreSQL for commercial purpose

Dear Sir

I am a developer of one commercial organization. We are going to develop some applications with PostgreSQL 7.3.3. I learn from some websites that it cost no charge for developing software with PostgreSQL in commercial environment. However, I saw the PostgreSQL is under two type of licenses, namely, X11-style license and BSD license for the following websites,

http://www.postgresql.org/licence.html

http://www.gnu.org/directory/database/servers/postgresql.html

Please kindly provide professional comment on this issue and suggest whether the use of PostgreSQL for commercial purpose is no license charge or not

Thanks & Best Regards,

Eric Yum

CK Life Sciences Ltd.

Finance & Administration - IT Team

Tel: 21261351