A well known PSP hacker that goes by the name of Dragula96 seems to have cracked the code in the PlayStation 3 firmware 2.20. The exploit he discovered allowed him to put his own "Hello World" proof of concept on the PlayStation 3. He's not sharing how he did it at the moment. He is still running tests however on how to run a simple game like Pong.
He mentions the console he was running the homebrew on had no modifications whatsoever. It will work on both 40GB and 60GB models. When more homebrew news comes out, we will be sure to update you.
[Hacker gives PS3 a homebrew hello]