Whats the real truth of Jailbreaking the ps3. Can it be done with multiple firmwares?

So iv been reading both here on the forum and online about jailbreaking the ps3. Some pages say that everything up to 3.55 is ok, other claim you can jailbreak any ps3.
Also some say by doing this you cannot go online anymore and play.
Also iv read someone say you need to buy some equipment to jailbreak it...

As you can see im a novice, but Im hoping someone could give me an head up about my ps3 4.20.
1. Can it be jailbroken?
2. Do I need to buy something to flash it, or is all readily downloadable?
3. Wil some games not work or can I not go online?
4 Is it possible to play games from HDD as on the wii?

Thanks in advance!

To the best of my knowledge, only older firmware can be jailbroken. Then there's CFW that will allow the PS3 to spoof later firmware. Higher firmware can only be jailbroken via downgrade which requires specialized equipment (NAND programmer and so forth) and is not for the faint of heart. Not sure how the CFW with spoofing goes relating to online experiences...

Edit: moved thread to more open-ended section of PS3.