Play IQ data in the soundcard
If the spectrum of your I/Q samples is centered at zero then you'll have to perform either AM or FM demodulation before routing any real-valued audio samples to a sound card. For AM demodulation you'll need to implement a complex-input "envelope detector" which produces a real-valued audio signal riding on a DC bias. (In a few days check the web page:

www.dsprelated.com

for a blog of mine describing different envelope detectors.) That amplitude-biased audio signal then needs to be passed through a "DC blocking" filter (a highpass filter whose cutoff frequency is very close to zero Hz) and the output of that filter goes to your sound card.  From Chapter 13 of my DSP book, the most common DC blocking filters look like the following:



where alpha is a number close to, but less than, one.

Now if your I/Q signal (whose spectrum is centered at zero Hz) is an FM modulated signal there are two common ways to perform FM demodulation to produce a real-valued audio signal sequence.  One way is unpleasant because it requires the computation of arctangents and the other way is unpleasant because it requires you to perform divisions. Oleg, search the Internet for "digital FM demodulation" and you will be able to learn about those two different FM demodulation methods.