how to use PostGIS with Postgres

We have PostGIS 1.1.1 installed  and I am trying to get it to work with
Postgres8.1.1 on our system.

Could some one give me a small sample script that lets me connect to
postgis from Postgres?

I have never used postgis before. I need to test its geo-spatial
functionality with Postgres.

Thanks a lot,

Yantao