SQL Server 9.0 (2005) & PostgreSQL Data Types

Hi,

I´m building an aplication with VB.net and SQL Server 9, but in the future it will be compatible with PostgreSQL (by another developer), so my question is, if anyone knows what "data types" in SQL Server 9 i must use to maintain compatibility with PostgreSQL, so that when the time come for the conversion i don t have to chage the "Data Types" on each table.

Any help would be apreciated.