Popular UK magazine "Games TM" is claiming that Rockstar have confirmed Liberty City Stories' release date to be October of this year.

Rockstar has confirmed that PSP title GTA: Liberty City Stories will arrive in October, shortly after Sony's handheld's European launch. Returning to GTA III's Liberty City, players control Toni Cipriani, a character in GTA III. Cipriani will be voiced by series veteran Michael Madsen, which will lend the main character the gravitas now expected of Rockstar's free-roaming universe. How the game will drain PSP's battery life remains to be seen...

We are currently trying to confirm this with Rockstar. Thanks to funkychunky for the news.

UPDATE: Unfortunately, Rockstar were unable to confirm this.