I found a couple tips on plank grilling in the grilling tips thread, but want as much info in advance. I have a 4 pack of small planks and will attempt salmon fillets tonight. What I know so far, mostly thanks to cblaisd:

1. Soak the plank at least an hour.
2. Oil before adding fish.

What I'd also like to know:

1. How reusable are they? How long do they last?
2. Do they clean up well?
3. What am I aiming for - smoke flavor? Any conflicts between seasoning/marinade & smokiness?
4. What else can I cook on planks? Meat?
5. Gas grill same as a charcoal grill?
6. What have I not though of?