I understand you can load your games onto your PS3 H/D and play them from there but do you need to have the game disc inserted, like with the Xbox360, when you play the game.

It depends... If you buy it from the PSN store, then you do not require a disc, but if they give you a code I recommend remembering it. I never personally bought any game from the PSN store, so if you decide to do that, I suggest having good amount of space on your Hard drive.

If you on the otherhand bought a disc, then you do need it to play the game. I hope I helped.

Yes mainly wanted to be able to load my store bought discs onto the HDD the same way you could on the PS2 but have been checking around and it looks less and less likely. There is somthing called KPack that is supposed to do it but apparently its just an expensive scam.
I guess SONY learn't from the PS2, I know I did which is why I have most of my favorites loaded onto a 400g internal drive
Cheers for your help

EDIT
There is also the the PS Jailbreak which is supposed to be able to let you dump the disk on a HDD but is around $160. Acording to this article http://www.ozmodchips.com/ps3-playst...chip-p-68.html SONY has put an injuction on the sales of the dongle.
If it goes to court here hopefully they will win against SONY like they did with the PS2 modchip.
But I doubt it.

EDIT
OZ Modchips & Quantronics have removed the PS Jailbreak dongle from their website so I guess they lost on the injuction...no real surprise