Thanks for the quick and helpful responses everyone.

@Pappenheimer - I never thought to look in the AUM Magazines for some reason I have never read them, don't know why.

@lemming - I like the method you have for breaking down the parts of the development and being able to easily slot new ideas into. I think this will be extremely helpful when I think of something that I want to add.

@Tempelbauer - I think the Spiral Model is going to be quite helpful having a visual aid is a great idea. I didn't think about breaking features down by required features, the optional features and the nice-to-haves I would have just had a massive list. I always find Subversion useful when I'm coding.

@FoxHound - When making levels/models is there an typical quant - cm ratio or is it just what I think is best?

Tom