PSX4Droid is a very popular Playstation emulator that was in the Android Market, that is right up until the Xperia Play launched then out of no where Google pulled the app for violating content policies. You can read more about that here. We aren't sure if they just finally pulled the trigger to pull the app, or if Sony and their exciting Xperia Play had a role in that.
Now it is time to play on, because in light of Google pulling the app, creator ZodTTD has released the game FREE for all to enjoy. He did say that "In the meantime, I’m exploring 3rd party markets and I have decided to make psx4droid free, based it on the open source software PCSX-ReARMed by Notaz, and made it compliant."
Not only is it free, but it is open source for others to work on and improve it. This is good news for all of us. I am assuming he will be continuing development for the app, as well as having others help in the open community. It is sad to see it resort to this, but hopefully better things come in the future for this app and anything from ZodTTD.