Mike is right on about the floscan installation. A less costly and simpler install would be a Navman 2100 or 3100 system. I have this system through my 5500 chart plotter display and am very happy with it. Just make sure you use a good quality filter. The 2100 uses a standard 2" guage. The 3100 is larger and capable of interfacing with your gps.The install is easy and straight foward. The whole thing can be done for 2-500 bucks.
Here is my tranducer intall.
