Remove the power source - battery. Make sure the battery gets air dried as well.
Make sure the entire inside is dried out before re-inserting the battery or power source. This may take a couple of days even if you use a hair dryer to dry the phone. The key is to dry the phone COMPLETELY.
After you have ensured the two thing above are done. Insert the battery and see if the phone will turn on or if the battery will accept a charge as you attempt to charge the phone. If it does you are all set if not .... You will either have to think about repairing the phone or replacement.