Welcome Dom and good luck!
Don't know where to begin? There's plenty of info out there, which can be overwhelming when you first start out. My suggestion would be to find a site or program where you can track what you eat. Saying that you are just going to eat better can be disastrous for many (at least when starting out).
My biggest suggestions for you for starting out:
Track what you eat (you can find many examples of places where you can do this online in this thread WeightWatchers/Nutrimirror/other places)
Start exercising: you don't have to start out hardcore, just walking around the block everyday or riding a bike is a start
Drink plenty of water.
Stay focused. If results don't go the way you think they ought to, keep on trying anyway.
Once again, good luck. If you need any advice, support, or help, that's what this thread is for.