Difference between Full Join and Inner Join in SQl Server 2005

What is the main difference between Full Join and Inner Join in SQl Server 2005 ?
As inner join retrive all records that match certain condition, similiary in full join will rreturn all records only where they match.
Also sugest me which one is optimal in Inner Join and Where clause.This question is being moved to the SQL Server forum.

ADMIN|||Inner Join returns matching records only

A full outer join returns all rows in both the left and right tables

Hope it is clear enough.