Sammy- My elec & gas is with AGL, and they do bill smoothing, they add up what they think you will use for a year, and average this out and set an amount for you...my gas is $11 a week, and my elec is $28 per week.

My phone bill is always the same, if there is any difference it is only small and I pay the difference.
With my water bill I pay $15 per week, and end up being about $5 in credit before the next bill is issued.