Best mysql configuration for 4GB dual core processor

Can anybody suggest me the best configuration parameters for mysql server. I have a CentOs 5 32 bit server with dual core processor and 4 GB RAM.

I am using the server for mailing so the I require an optimized my.cnf parameter list so that it would give the best performance. I am not a mysql expert so a list of configuration parameters for the my.cnf file will be nice to me.