This deck is ready to play right out of the box. It includes cards not just from Mirrodin Besieged but powerful cards from other sets as well. It even has a sideboard. This deck is tournament ready as soon as you open it.
Here is the deck list:
2 Drowned Catacomb (M11 Rare), 7 Swamp, 10 Island

1 Doom Blade (M11 Common), 1 Hand of the Praetors (SOM Rare), 2 Consuming Vapors (ROE Rare), 2 Contagion Clasp (SOM Uncommon), 2 Deprive (ROE Common), 2 Mana Leak (M11 Common), 2 Phyrexian Vatmother (MBS rare), 2 Smother (WWK Uncommon), 3 Preordain (M11 Common), 4 Corpse Cur (SOM Common), 4 Corrupted Conscience (MBS Uncommon), 4 Foresee (M11 Common), 4 Jwar Isle Refuge (ZEN Uncommon), 4 Necropede (SOM Uncommon), 4 Plague Myr (MBS Uncommon)

Sideboard
1 Doom Blade (M11 Common), 2 Go for the Throat (MBS Uncommon), 2 Smother (WWK Uncommon), 3 Deathmark (M11 Common), 3 Flashfreeze (M11 Uncommon), 4 Negate (M11 Common)