Stored procedure basics questions

Hi everyone.

Windows 7, I have installed PostgreSQL and Lazarus, both 32 bit, and have been doing some examples and explorations on the combination, and so far so good. I do have some old database background.

As part of my planning on things I'd like to learn about and do, I have these questions, for which I would very much appreciate some guidance :

1. If one puts stored procedures in the database that use basically the PL/pgSQL, or just SQL, I understand that they are executed by the Postgres server, with or without results returned to the client. Right?

2. If so, then, I suppose the stored procedures would be independent of the Client, perhaps some types are and some are not? If so, which types are independent of the client and which are not?

3. Can stored procedures be called via an ODBC driver? If so, any restrictions?

Thanks!