The main problem is that a sound like a clap is a complex waveform and is not just one frequency. That makes it difficult to recognise.For getting at the frequency content of a waveform look to use a FFT. However that gives you in effect a list of all the frequencies and their relitave strengths. Recognising a specific sound is a lot more complex because its FFT will change over time.While you can implement a band pass filter digitally it will not be a very high order filter due to the lack of processing power of the arduino.
http://www.sparkfun.com/products/10024That might help you, but he's right, claps are difficult to differentiate from other complex high frequency waveforms. If all the others are low pure tones and less brief than it will be easy! Read the datasheet within my link above.
Implementing an envelope detector might help with capturing claps - the envelop is pretty distinctive. Basically rapid attack and no noticeable duration before decay. The only frequency-dependent part is choosing a time-constant for the decay - wants to be short but long enough to not count a single clap as several events.
but everything has a fundamental or a dominant freq, so you can basically search for a specific freq something likes to resonate at.