Problems with speaker and microphone

Hello everybody,

I'm new at arduino and I just started with the simplest projects and now I'm trying to make an arduino receive a sound by a microphone (I'm currently using the BOB-09964) and then make the same sound be emitted by a speaker. The first part is okay, i can make the arduino identify the sound (I used the code on this site Inkling), but I'm having problems trying to make the sound be emitted.
If anyone could help me with some guidance, links or functions that may work, I would appreciate.

Thanks in advance

there is written code for playing both 8bits and 16bits sound using pwm.
search for "pwm playback"

http://playground.arduino.cc/Code/PCMAudio

How long is the sound? You need extra memory for more than a fraction of a second.