A temporary boost to an attribute adds to the attribute only for purposes of stat modifiers to skills and damages, lifting, Stat rolls, and ability to take attribute damage.
A permanent boost, (or in Pathfinder, even a long term temporary boost,) however, provides its effect as if it were full points change in the attribute, increasing derived abilities as well. A non-temporary stat gain to Int will affect skill points; to Con, Hit points per HD; Wis and Int affect spells.
There are two other implications of temporary boosts, however, that need to be remembered:
The first: the Damage principle
1) Damage to X comes from Temporary X 1st
2) Temporary X does not heal damage to permanent X.
The damage principle means that, if you've boosted people's stats, and are using attribute damage attacks (be they spells or monster powers, or even houseruled critical effects), losses that don't do away with all the temporary points are non-issues long-term. If I use a spell to gain them, and gain 4 points of Int, and the mindsucker pulls 3, the next day, when I cast, I still get all 4 back; the damage is gone.
The second is that (usually) Temporary Bonuses don't stack. Only the best applies. Permanent bonuses usually do stack.