Hey Milton - good question! You'd think that Capcom would have released one or two of them on Steam or GOG by now... Hmm. Back in the day I used a Japanese middleman service to buy the Sourcemod version of RE2 from eBay Japan, and bought the others from regular old eBay UK, but can imagine they demand a pretty penny nowadays. Outside of PSN, I'm not sure if the classic games are available digitally at all.