My lake (in Missouri) is worried about the zebra mussels also. I wash my boat at the car wash using high pressure/hot water to kill them, and let the boat dry before the next outing which also kills them.
What I am concerned about is that people think there is no way to kill them when in fact they are a living thing, and there are a lot of ways:
1) Regular old water above 104 degrees F kills them.
2) A mild Water/Bleach solution kills them.
3) Water/KCL solution kills them.
4) Drying the boat out kills them.
They have even proved that zebra mussels can be eradicated from a totally infested lake after the fact using Potassium Chloride (KCL).
Here is the EPA write up about the successful eradication that was done in 2006 at Millbrook.
http://www.dgif.virginia.gov/zebramussels/ (Message edited by tj_in_kc on July 07, 2009)