Thanks guys, will duly check those sites out!
The adoption centre recommended that we should wait another month or so before we start them on a raw diet since the kittens are only 2 months old.
I cheated a bit the other day and gave them half a raw chicken neck each, I freaked out when one of the kittens started growling as she was eating so I took it away -__- is that part of natural cat behaviour when eating raw meat?