It's a relatively new use for alert animals so there aren't many organizations yet with trained dogs ready to place. Debra Manzella, over at About.com: Diabetes, in her post, Hypo Dogs to the Rescue! lists a few groups that provide alert dogs for people with diabetes, primarily type 1. I've listed them below along with another I found.
Dogs4Diabetics
Heaven Scent Paws
All Purpose Canines
PAWS For Diabetics (Australia)
You may also want to consider having your own dog trained. The organizations above are a good starting place.
News article:
Hypoglycemia Alert Dogs Offer Assistance to People with Diabetes
Photo of Hunter and her diabetes alert dog Diva from childrenwithDIABETES.com.