I and my brother have one ps3 and we have 2 different psn accounts
if one of us pay for it can we both use all the features + free games?
it doesn’t make sense for us to pay 100 bucks

Naturally. All PSN games, demos and content are downloaded to the system, so I don't see why this should be any different.

hmmm

for games probably yes while the account its on the same ps3.

if u delete the account u loose access to it.

for xchat probably not, but we arent sure about that yet, but that usually linked to the account no the console.

unless sony follows what they do to games.

Cross game voice chat isn't part of PSN .

okay Sony says"When you subscribe to PlayStation Plus, you’ll get free games and DLC"

so my question is how does sony prevent the user from playing the game if he/she doesn't renew his subscribtion

i don't care about xchat,

mostly i care about the free games , DLCs  and free trials/betas

I suppose you need to be connected to PSN...hmmm, I see where you're coming from.

You could play on the same account, I guess.

i thought so, that's not good. This also means you have to be connected to internet all the time for playing the games

Sony should explain this.

generally when purchasing something its accessible by all accounts on the system...but since this is essentially a rental, idk if it will work like that. 

What could happen is that you'll be able to play offline fine, but when you go online, it will check for the presence of PSN .