We used Insulated Concrete Forms (ICF's), made of 2 layers of styrofoam held 8 inches apart by nylon webs. These are stacked like blocks and zip-tied to hold the concrete when poured and remain as an insulation layer afterwards.

Transporting the forms to the property - the "Van'o'Love II" has been a workhhorse and Peter's trailer has come in quite handy:

The ICF's are staged and ready for assembly:

We were too busy during the slab pour to take pictures. Here is one of me finishing the slab with a power trowel:

Cheap labor (AKA: skidge):

Drains are placed in gravel to relieve any water pressure that might build up against the foundation wall. The blue membrane (top picture) is waterproofing.