YourPSP.com have created a Liberty City Stories section containing various bits of information and three (low-quality) digital screenshots.

An astounding technical achievement, Liberty City Stories pushes the PSP to it's absolute limit, resetting the public's understanding and expectations of what is possible on a hand held gaming system. See Liberty City like never before. Experience a whole new adventure in three classic boroughs: Portland, Staunton Island and Shoreside Vale. Dripping with nostalgia, each neighbourhood has been meticulously created for the PSP with all new businesses, pedestrians and adventures. An all-new cinematic adventure that follows Toni Cipriani's return to Liberty City, his involvment with the Leone's, and their bitter turf war against the Sindacco Family, the police force and the Mayors office. Freedom to play the game your way - play through the varied missions, or interact freely with the sprawling city. Drive the best vehicles from the Grand Theft Auto universe. Get on two wheels with the debut of motorcycles in Liberty City, jack new cars, trucks and other vehicleswhile they cruise the streets. Lookin' Sharp! For the first time different outfits have been made available to the player in Liberty City. Amazing 3D visuals on the PSP due to enhanced draw distance, new lighting and shading models, as well as real-time reflections.

The release date is shown as 1st October 2005 and the game is recommended for persons of 18 years and over.

Source: GTA-PSP.net