[Gandalf Parker]

Those are pretty good.

Also, send out scouts to find the enemy on the OTHER side of your enemy.

A) Having a scout in the AIs territory tends to cause the AI to build up an army there. So dont keep scout in his provinces near YOUR border, keep them in provinces near the other guys border. Bounce the scout back and forth between the two AIs forcing them to build up armies on each others border. It ties up their funds. And is likely to make them fight each other.

B) You might even be able to find a really weakened province in their war and take it with the scout (or better yet a sneak army. Put one turns money into PD for it, then recruit there. It will force the enemy to shift attention the other direction for awhile.

C) Send equipment to the AI on the other side of your enemy. In many cases it can be things that will assist that AI against your enemy, but not be of much use to them when you attack your old buddy. Such as; if they are on the other side of Ermor then send them the herald spear that does solar spells vs undead. If its Ctis that you are working against then send them protect vs poison. Neither item is likely to cause your troops much problem when it come time to attack your old ally.