~Marigold~ if you are wanting to use fondant, you can buy it already coloured, saves you colouring it yourself which is a right royal pain if you use too much and it gets sticky etc. If you're a bit nervous about the whole fondant thing, you can use buttercream too.
If you do use pudding tins or the like, (Wilton's are great, but $$$) I would suggest when you are baking you put a funnel in it. I made a little one myself and put it in the mixture and the cake (butter cake sponge) was cooked throughout. I made a 'Lady Bird' cake which is also a dome shape.
I had my cake frozen to make it easier to cut and ice without it crumbling and ruining the icing etc.