Multiple List boxes leading to a query

[Nazgul79]

I have two "lookup" tables linking into one primary table. i want a from which has two list boxes, one for each table. the user makes a selection in list box 1, and 2 presses a button and the button runs a query which checks the primary table and returns a result in a subform on the same main-page. i have no idea how to do this. i have searched the forum for help on list box and have some info to start with but would like some help on how to do it.

to summarise:

Select:
list box 1: Service type
list box 2: Suburb
press OK

search criteria checks table containing companies that provide selected Service type in selected suburb and gives the information in a subform.

any suggestions???