First off skip the rice. It is absolutely useless. It will not help you fix your phone. All it does it provides a false sense of security. It will not clean your phone, it will not prevent corrosion. check on here Don't Put Your Device in Rice. Here's Why... for more info on that
Second, stop continuing to try to charge, sync or otherwise use your phone. This potentially can make a bad situation worse.
The very first step I would take is to disassemble your phone. Use these guides to disassemble your phone. Take a careful and close look at all components and connectors. Truly assess the damage. Look for major corrosion, evaluate the pins in the connectors etc,. Take a look at all connectors as well as cable ends. To properly clean your logic board, you will have to remove all the EMI shields. Once you got the gross contamination cleaned, use 90%+ isopropyl alcohol and clean your parts some more. For a proper cleaning, use this guide. It was written for a Apple iPhone 3G but it is still pertinent to your phone as well. I can not stress the importance of a good cleaning enough, so do it over and over while replacing the alcohol after each cleaning. Do not use compressed air for the cleaning since that can drive liquid as well as corrosion particles into areas that will cause trouble later on. Also, you do not need to leave it to dry for a day. Isopropyl alcohol in the higher concentration will evaporate quickly and dissipate the water. Or you can dry the board in an oven or equivalent at 220deg F (not higher;-) for a few hours. Best way to clean it would of course be through an ultrasonic cleaner. Consider professional help with that. When it is properly cleaned, replace the battery. This is a must and not an option. All these steps are to avoid delayed failure caused by corrosion. Once all this is done, reassemble your phone and reevaluate. The importance here is the cleaning. Keep in mind that water damage is the hardest to troubleshoot and to repair. Hope this helps, good luck.