My parents' cat has diabetes. They had to get a special litterbox for him so they can check the blood sugar levels through the urine. It uses bird seed as the litter (non-absorbant, but he can still bury his stuff). It took a while for them to figure out how much insulin he needed. It's actually the same insulin as humans take, just a smaller dosage. They also bought a human blood sugar monitor to test his levels while they were figuring out dosage.
As far as the insulin goes, it depends on the cat how well it would do. My Chloe wouldn't do well at all, but my parents' cat, Smokey, is great about it. My parents "shoot the cat" at 7am and 7pm each day and Smokey actually goes looking for his insulin around those times. He doesn't know what it is, but knows it makes him feel better.
I think my dad has used that same message board sweetpeach posted. It is a lot of work, but it doesn't need to be too bad. The biggest challenge for my parents is when they are out for a while and need to adjust his times, or if they are going on vacation and either need to bring him or find someone to give him his insulin twice a day.