Could be oral thrush, or it could just be that you need to brush your tongue more (bacterial build-up in your mouth is what causes your tongue to begin to accrue a white coating). It doesn't seem like you need to be too concerned about it (sorry I just noticed the picture now lol...I'm a little slow!). On the plus side, you have really nice teeth!
Thanks for the nice teeth comment. It's apparently related to my acid reflux/heartburn/digestion issues. I showed the doctor and he wasn't too concerned, thankfully! x