Update on the speedometer- I was able to get it working again thanks to the help of all of you.

I will say that it was difficult, though, because the piece of wood I hit must have been VERY soft. I would estimate that probably 3-4 inches of the pitot was jammed.
So, here is the official procedure for getting something like that opened back up:
1. Pray to whatever you pray to.
2. Make sure you have plenty of your favorite beverage on hand.
3. Get a set of small drill bits (less that 1/4" in size on down), a pair of vice grips, a large paper clip, and have a garden hose with a nozzle accessible.
4. Run the lower unit all the way up and locate the pitot disconnect near the gimbal housing. Unhook the tube by pulling it toward the sky, then turn the pitot plastic assembly that the tube came off of to the starboard side of the engine. It will lift out, giving you access to the hole the pickup tube is connected to.
5. Use the hose and nozzle to blast the debris out.
6. If 5 fails, unfold paper clip and try to clear pickup at hole on leading edge of lower unit. DO NOT force it in, as this may puncture the tube itself.
7. If 6 wouldn't allow the paper clip to move very far, start with the smallest drill bit you can find. Put it in the vise grips and slowly turn counterclockwise by hand (you're "hand drilling" the debris out). Keep the nozzle in place and continuing to apply pressure during this process. Hand drill until you see a steady stream of water. Increase size of drill bit until you have cleared debris. Again, DO NOT force it in, as this may puncture the tube itself. Turn it by hand and be patient.
8. If 7 didn't work, and you have used the largest drill bit possible, go back to the paper clip and unfold it all the way to utilize all of its length.
I had to do 1-8, not sure what step 9 is outside of pulling the lower unit to access the tube from the inside. I had the largest drill bit I could fit in the hole (maybe 1/8"? can't remember now) all the way in, and it still didn't clear it. It wasn't until I went back to the paper clip that I could get enough length in there to unclog it. The hand drilling process removed a TON of wood, though.
_________________
Paul
2007 Four Winns Horizon 220Mercruiser 350 Mag MPI w/ Bravo III Drive
2004 Ford Explorer Limited (V8-AWD)
Pomme de Terre Lake (Southwest Missouri)