Reference plans:
http://ana-white.com/2010/05/furniture-plans-loft-bed.html
http://ana-white.com/2011/04/fire-truck-bed
The plans for the loft bed were accurate and easy to follow. Used pine, primer and paint. My kid was inspired by the INCREDIBLE Fire Truck Loft Bed (http://ana-white.com/2011/04/fire-truck-bed). Thankfully the Monster Truck can be taken off with a few screws once he outgrows Monster Trucks (giving it 2 to 22 years).
I did go back and anchor the bed to the wall in 4 places (he likes to bounce). In addition, anchored the ladder to the floor. Added 2 additional 2X2 under the bed for a total of 3 spines to support the planks and a thin piece of particle board (used for backing in book cases) to help distribute the weight over the planks. Blame it on over-protective parenting. Also added a shelf between the bed and wall to hold his music stash.