Gibeon and Prayer

Okay, so i have a new favorite Bible story. Gibeon:) Allegedly I heard this story in high school (or maybe jr high), but i dont remember it. (i must've been absent that day!) Anyways, I love the whole book of Joshua. It is full of war, deception, scandals, death, and broken covenants, but also matched with love, promises, forgiveness, and restoration. Anyway, back to the story. I am sure most of you know this story, but i just want to recap for you.
So Joshua and his army demolish Ai and burn what is left to the ground. Next on the list would probably have been Gibeon. the gibeonites knew this, so they came up with a cool plan. (i think it is Joshua 9?) some of the men of gibeon dressed up in old, tattered clothes and shoes that had seen better days. they also brought moldy, crumbly bread (which i think is a great addition to their credibility). They took the short trip to the Israelites camp and told them that they had come SOO far and had heard about their God (YAHWEH) and asked Joshua to make a league (or pact) with them. the gibeonites even went so far as to say "we brought this bread fresh out of our oven...now it is moldy...". What LIARS! however, their tactic worked, joshua fell for it(because he didnt pray about it) and made a league with them.
Here is the clincher. God commanded that the Israelites destroy allll of the inhabitants of the land. so, should joshua have broken the league with the gibeonites and killed them all (to honor God's covenant), or should he have done what he did and honored the covenant? your input is greatly appreciated (although i have already made up my mind and will post it later:))
I have learned so much from Joshua. he makes mistakes - of enormous proportions - just like we do...all because of a lack of prayer.
Recently I have been reading the book called A Woman's Call to Prayer by Elizabeth George. i just started it and been reading about the 10 reasons we dont pray. i can only say that the reason we dont pray as we should is selfishness. we "dont have time" because we are selfish and would rather sleep or "just chill". we "forget" because we are selfish and thinking about how we can be self-sufficient and so on. prayer is vital to our spiritual walk with God, we cannot afford to be selfish in our pursuit of life...what is life is Christ is not in it?