The PlayStation Store is now open for a range of PlayStation Suite-certified Sony Ericsson Android phones in Japan. The Store will be launched in other countries soon but no specific date has been announced. 
There are 23 original PS One games available in the PlayStation Store right now including some free games like Minna no Golf 2.
Xperia Arc and Acro are the fourth and fifth phones to get this coveted certification. Other devices to get this certification are Xperia Play, Sony P tablet and Sony S tablet.
More phone and tablets are likely to get this certification including the Arc S, Nozomi, and other Xperia range devices with Android 2.3 or higher. Sony also plans to release the PlayStation suit SDK so that other Android manufacturers could also certify their devices and to make PlayStation game store available on non-Sony Android devices.