Capcom in Japan have a separate Twitter account dedicated to retro games, named Capcom_Retro. Lately, they’ve been using it to gauge which of their PlayStation One games fans would like to see on Game Archives on the Japanese PlayStation Network.
Keep in mind that this is only for Japan, but if you’d like to make your voice heard, you can follow the Capcom Retro Twitter feed, and send them a tweet with the hashtag #Cpga2011. Keep in mind that some of Capcom’s popular PS1 games are already on the PlayStation Network.
Naturally, this doesn’t guarantee you’ll see the games of your choice going up right away, but it will help give Capcom an idea of what their fans want and should help sway decisions in the long run.