functions and triggers

I'm trying to create a function and triggers. I need to know if there are
ways to create a function and call it by a trigger. This function would
need to look at three columns in a table and insert into 2 columns in
another table.

Is this possible and which language would you use. I'm a beginner in
PLPGSQL. I have read all the doc's on the internet but I can not find any
examples of something close to what I need it to do.

Thanks

Robert Stewart

Division of Communications

Office of Infrastructure Services

Governors Office for Technology

Commonwealth of Kentucky

W 502.564.4287

P 877.543.0473

C 502.330.5991

Email: RoberD.Stewart@mail.state.ky.us