I built a Pulsecounter & Datalogger using the new Arduino Ethernet and Arduino22 environment.
It includes SD card logging, webserving, NTP clock synchronization over the ethernet.
You can find a description along with the code (GPLed) at Only_Dead_Fish_Go_With_The_Flow: TomWare Arduino-Ethernet Datalogger
I will have to evolve it including FFT capability of high frequency multi channel analog samples. Will keep it posted.