GTA IV's multiplayer modes revealed

From here. The info comes from a Spanish PlayStation magazine. The modes are:

Hangmans NOOSE
Car Jack City
Bomb da Base
Bomb da Base II
Mafia Work
Team Mafia Work
Deathmatch
Team Deathmatch
Turf War
Cops N Crooks
Race
GTA Race
Deal Breaker
Free Roam

Apparently there are another two as well, giving 15 in total. Online play supports 16 players, and users will be able to create their own characters for PSN and Live games. There are more specifics here.