GTASampling rate of up to 44.1 kHz
512 kB of audio memory via psone cd audio.
The main theme is "Gangster Friday" by Craig Conner
Also contained audio from various artists. source:
GTA 2cd audio via the psone
44 k sample rate. The audio was mixed by various djs each contributing four to five tracks to 11 radio stations. source
GTA 3Via ps2
Sound Memory: 2 MB
Sampling Frequency: 44.1 kHz
Output: Dolby Digital 5.1 Surround sound,
most tracks where selected from various artists for the different radio stations. The dj's and misc tracks are by Craig Conner and Stuart Ross.
GTA IVVia ps3
At it's max the ps3 is capable of 7.1 dolby digital via bluray and an hdmi cable.
" Michael Hunter composed and produced the theme song called Soviet Connection and incidental music for the original game" 
Again this iteration of the game used a veriety of different radio stations each filled with songs from a verity of artists. sources