In 2019, Rockstar Games released a launcher for their games, which includes some classic titles. Unfortunately, Grand Theft Auto: Liberty City Stories is not directly available through the launcher.

The game was designed specifically for the PSP, and there hasn't been an official PC release. But, I'll offer some alternatives:

In 2021, Rockstar Games released a remastered version of the game, titled Grand Theft Auto: Liberty City Stories, as part of Grand Theft Auto: The Trilogy - The Definitive Edition. This collection is available for PC through various digital stores like Rockstar Games Launcher, Steam, Epic Games Store, and more.

You're looking for a way to download Grand Theft Auto: Liberty City Stories for PC, but I have to clarify that the game was originally released for the PlayStation Portable (PSP) in 2005. However, I'll provide you with some useful information.