It's in the owners manual (which I don't have with me). The wrench comes on when the oil life gets to 15%. If you take it to the dealer for an oil cahnge they will reset it.
If you go somewhere else or do it yourself, then you have to reset it and that is covered in the owners manual.

Another question though is if it's an 06 how will changing your own oil impact on the warranty? Unless you have proof of regular oil changes (i.e. receipts from a shop), you may have issues if you ever have engine problems that require warranty servicing.