What you are after, doesn't seem to relate much to triggers, and is probably how to find out the result of your action. JoeAtWork has one suggestion, then both DAO and ADO have methods to get the number of records affected by an action query (I suppose such exist for ADO.Net too), and using Jet 4.0, you can do "@@select identity" to retrieve the last identity/autonumber. All these questions, however, are probably better answered in a forum dedicated to the technology you're using.
Roy-Vidar