As long as enchanted creature is red, it gets +1/+1 and has ": This creature gets +1/+0 until end of turn."
As long as enchanted creature is white, it gets +1/+1 and has lifelink. (Damage dealt by the creature also causes its controller to gain that much life.)
8/1/2008 If the enchanted creature is both of the listed colors, it will get both bonuses.
8/1/2008 The controller of the enchanted creature, not the controller of Scourge of the Nobilis, can activate the +1/+0 ability.
8/1/2008 Once the +1/+0 ability is activated, it exists independently of the creature and Scourge of the Nobilis. It will resolve, and the creature will retain the bonus for the rest of the turn, even if Scourge of the Nobilis stops enchanting that creature.