I bought this the other day, and have got it to work by doing the following:
send trigger pulse, wait for the echo holdoff, count until the pin i have goes high, then count how long it stays high
So this is working, as I am getting data which is distance dependent sent back to me over the UART. I am not sure if it is accurate yet, but I am about to try to use the following equation to convert it to cm.
cycles_high * 1/2 * ( 1s / 20 000 000 cycles ) * 340m / s
So my real question is... how hard is it to use ICP to get this to work, I'm using an atmega168. I should also note I would probably be using the other timers for driving my motors with PWM.