This is what I got from the Official PSP website (Playstation.com)
There are a million stories in Liberty City. This one changes everything. Once a trusted wise guy in the Leone crime family, Toni Cipriani was forced into hiding after killing a made man.
Now he’s back and it’s time for things to be put right. The streets of Liberty City are in turmoil. Warring Mafiosi vie for control as the town begins to self-destruct under waves of political corruption, organized crime, drug trafficking and union strikes. No one can be trusted as Toni tries to clean up the mess of the city's chaotic underworld. Deranged hit men, morally depraved tycoons, cynical politicians and his own mother stand in his way as Toni tries to bring the city under Leone control.
Forced to fight for his life in an odyssey that will shake Liberty City to its foundations, Toni must use any means necessary to secure his place in the leadership of the Leone family in a town up for grabs
Developed by Rockstar Leeds and series creators Rockstar North, Grand Theft Auto: Liberty City Stories will be available exclusively for the PSP (PlayStation Portable) this October.
Downloads and Video Previews
9/9/2005 GTA: Liberty City Stories
9/30/2005 GTA: Liberty City Multiplayer
9/12/2005 PSP GTA Stories spun on Web
New Web site for portable Grand Theft Auto details Rockstar's next rampage through parody, external Web destinations.
10/3/2005 PvP confirmed for PSP GTA
Rockstar's upcoming Grand Theft Auto: Liberty City Stories will feature deathmatch, capture the flag, and assault variants; new trailer also released