I have the same problem - dropped mine "head first" into a cup of coffee about 6 months ago.
A friend researched my problem, and suggested rinsing in distilled / deionised water (to remove any contaminants) then drying, then rinsing in isopropyl alcohol and drying again.
Trouble is, after removing the back cover and battery, there seem to be two absolutely tiny "torx" style screws which look like they need undoing to dissaamble the phone further.
That's stumped me so far.
Anyone else got any suggestions?
Richard.
Richard Lambert, June 2008