Selectbox Total Calculator

Hello,

we have an online store we are setting up, where chargable options are
offered, what we are want is the "our price" to update dynamically when an
option is selected.

Here is a product page:

http://www.mansuntv.co.uk/pedro/stor...sp?idproduct=9

Each product may have a different amount of options, this one has 3, some
other products may have 4 or even none.

Any ideas on how I can get this to work.


Many thanks in advance.

Andie