The affected creature gains a +4 morale bonus to Strength and Constitution and a +2 morale bonus on Will saves.
In addition, when making a full attack, the affected creature may make one additional attack with any weapon he is holding.
The attack is made using the creature's full base attack bonus, plus any modifiers appropriate to the situation.
(This effect is not cumulative with similar effects, such as that provided by the haste spell, nor does it actually grant an extra action, so you can't use it to cast a second spell or otherwise take an extra action in the round).