You probably can't save it.
But hey, you've got nothing to lose, so here's what I'd suggest:
1: REMOVE THE BATTERY! Unfortunately, this is probably a step that would have been best taken before the phone went into the wash.
2: Disassemble as much as possible.
3: Submerge in clean water, allow all parts to rinse as thoroughly as possible.
4: Allow parts to dry for a day or more.
5: Reassemble and test.
(These steps were suggested by a camera repair expert in something I read once for what to do if your camera gets dunked in saltwater.)
Water, in and of itself, will not harm most electronics. I worked for a while in an electronics board assembly shop, and the last stage in manufacturing was to run the circuit boards through a consumer dishwasher. (Cold water, no soap.)
Having power to the thing while it went through the wash probably was the worst factor here. (Okay, that or the soap.) The battery may be fried and I'd encourage you to test with a new/known working battery after rinsing.
I truly believe the water was probably not the worst thing for the phone. Soap, and physical shock of the washer, and having the battery in were probably worse.