Via Joystiq a PC version of Grand Theft Auto 5 made its way onto Amazon sites including France, UK, and Germany. Currently GTAV is only slated for Xbox 360 and PlayStation 3 with maybe small hints at PC, but no confirmation. You can find the listing on Amazon France here. Amazon listings have often leaked information, which has always been a hit or miss.
This isn't a confirmation, but it definitely fuels the rumors that Rockstar could be working on a PC version of GTAV. The well known petition toward Rockstar to develop it for PC is currently at 145,561 with a bit over 4,000 signatures left.