As I see it, a pension is just a savings scheme designed specifically for old age. The reason pensions per se are preferred rather than other forms of savings (eg ISAs etc) are:-
a) the contributions made are tax-deductible up to a certain limit (so for evey £100 you put in, the taxman puts in 28% for a basic rate tax payer)
b) your employer may also contribute.
The downsides are higher administration charges, and the fact that your money is tied up until you reach pension age as well as the fact that there are some restrictions as to how you can access the money at pension age.
If you are currently a SAHM then the benefits above may not apply, but you will be hit by the downsides. If you eventually intend to return to work you may be better off putting money aside in some other form of savings account (e.g. an ISA). These savings could either be built up over the years or could be used to fund lump sum AVCs when you return to work (thereby getting the additional tax relief at that point).
Stakeholder pension is also an option. Here you don't get any of the benefits listed above but the charges are capped. If you want the discipline of not being able to access the money this may be a suitable route.
You should be able to find a good independent financial adviser who can talk you through the options.