Hi Mike!
Actually there are now a lot of answers to basic questions. First save yourself a lot of research by knowing that speed = PSI! As for the PIC code you can find it here at:http://www.picbasic.co.uk/forum/showthread.php?t=19572. For me I needed a "differential" pressure sensor from Seroflo ([email protected]). The reason for a differential is that as my sub dives pressure will increase so you have to subtract out "depth" pressure (Static Pressure) from the pressure on the bow (velocity Pressure). One technique I have used with my compass was to mount the sensor on top of the PIC. If you are using a surface mount PIC you will see the PIC fits comfortably under just about any sensor. You can use a CAD program to design your PC board and then convert the CAD drawing to Gerber files. It helps to create "Layers" in Cad that you can turn on and off so you can create you solder mask and "ground plane". You will probably end up with a double sided board so you can make one side say in red traces and the other side in blue traces. Do not forget to specify plated thru holes! Your board size will most likely be .625 x .625". About the only other design consideration will be to isolate the sensor from the water. Hope this helps.

Best, Ed