Originally Posted by Blackus17
It's been 4 years of Galaxy S I9000 and no developer has yet developed a method to turn off the capacitive button light. This is very necessary as it could help with the very low battery capacity. I strongly request developers to concentrate their skills on this, to disable the light and thereby prevent the irritation to eye during the night & save a lot of juice.
Pardon me if I misunderstood your question.
If you just want the buttons not to turn on when receiving an sms (i.e. acting as notification led) then CyanogenMod has that option, just go into Settings->CyanogenMod->Audio->Quiet hours (or something to that effect), set from, say, 2:00 to 1:59 (all day minus 1') and check last option (Dim LED or something).
If you want them not to light up under any circumstance, well, I don't think I'd use that setting but I guess it'd be nice to have!