what do you do with the fellowship pass,also ive a note with the number "--0-" on it ?

Give the fellowship pass to Braffit. All you get is some information. the --0 note is part of a combination you need to open a T'rang safe, but in my opinion, it's not worth it, it makes the T'Rang hostile, and you don't get anything good out of it.

I also found out if you read it it gives you a hint of good weapon to use on Al-Sedexus....

that weapon is kinda useless. By the time you get to Al-Sedexus, you have access to a lot more fun stuff. Besides, only a Bish can use it, it's a polearm, which you can't get skill points for. (if the staff were any deadlier, it'd be worth being a valk for a level to get polearm skill, but it's not)

As I don't want to cause confusion, I just divide the answer into two.
1) the fellowship pass is for Lord Braffit. You give it to him and he tells you the location of the key for tomb in monestery. No xp reward though.
2) there are altogether 3 notes with number that you can find in t'rang area. The 3 nos hint you about opening the lock at the restricted room. The weapon inside is a polearm for bishop, psionic and monk that can cast nuclear blast. To enter the room without pissing off the t'rang you can search the forum. There should be enough informations about it.
Also it seems that someone above is confused about the pass. The note that really hint you about weapons vs Al-Sedexus is the one in the prison in lower monestery with a rapax skeleton. These weapons can be found in the tomb in lower monestery using the key stated above. They are a sword and a bow that caused double damage vs demon. However no one seems to be using them to fight Al-Sedexus because both of them are crappy once you reach the rapax area, even counting the bonus vs demon. eg. the sword has a displayed damage of 5-14, and we double it to 10-28. But the best sword in the game has a displayed damage of 5-40, with much better bonus overall.