Monteriggioni
It is located In Monteriggioni. Just go near the Villa and you will see the crypt.
Whenever you buy a painting at any art shop around the various cities, the painting is automatically hung in the Monteriggioni villa, you do not need to put it there yourself.
All you need to do is go back to monteriggioni villa and equip it in the armory (the room with a bunch of weapon racks)
you must complete all 6 tombs in the game and place the seals you get in the chests (in the tombs) on the statues of the assassins in the monteriggioni villa and the gate will open to receive Altair's armor. http://www.youtube.com/watch?v=imRdq4gU4pg
There are eight statuettes, all of which are located in Monteriggioni (Mario's villa.) A walkthrough detailing the exact locations of each statue can be found here: http://halo2and34u.com/Assassins_Creed_2_Statue_Locations.aspx
No. You are actually in the Auditore Villa.
it just goes into it when u steal
The assassins crypt at the Monteriggioni Villa contains 6 statues of famous assassins. When you collect all 6 seals from the various assassin's tombs, it will grant you access to Altair's armour - the protagonist from the first game.
It's in the Northern part of the walled city of Monterigionni.
After unlocking Altair's armor in Assassin's Creed II, the next mission involves returning to the Villa Auditore in Monteriggioni. You will then need to progress through the story, which includes missions that lead to the eventual confrontation with the Borgia. The gameplay continues to unfold with a mix of exploration, assassination contracts, and the overarching quest for revenge against the Templars.
Very simple, you get after leaving Florence (not for good) but It isn't that far into the game. Hope there are no spoils in there! :)