in fallout 3 and new vegas, if you accidentally shoot someone, and put away your weapon the would stop attacking you. i'm looking for a mod for oblivion that does that too, any suggestions?

Hold block and hit activate. If they like you,they yield.

well that's a weird key combination, in fallout you just holster your weapon, anyway will this work on guards? i will try ASAP

If you commit a crime, resist arrest, and then yield the guard will talk to you and attempt to arrest you again.

As a side, I quite like the combination of buttons, makes me think I'm cowering (block) and yelling for mercy (activating).

Me to, makes sort of sense in a sword fight you go into a defensive stance and tell the other that you want the fight to stop. In a gunfight you put away your gun.
Friendly/ neutral npc you have hit will usually accept you yield, guards will try to arrest you again same as the police do.
I managed to hit the count of Skingrad with spells during a quest so he attacked me, but accepted my yield however a friendly sheep kept attacking the count making everything pretty confusing.

when i asked if it would work on guards, i meant when i was helping a guard kill someone, but i accidentally hit him. he turned hostile and was chasing me while 30 feet underwater

Yes it will work, however if the guard see the attack as a crime he will arrest you, just pay the fine.

alright, thanks for the help

I'm just repeating for emphsis... xD
Block+Activate button(A)= Wield.
Although sometimes they'll reject it, which under certain circumstances is understanding.