Display records in a form depending upon lookup selection

HI, i've created a form with lookups to another form. I want the user to be able to select an item in the lookup field and depending upon their selection, information is shown to the side of the form fields.

For example:

User selects Country. If user selects Australia, a message displays to the side of the form which says "Australia has these States..(and then pulls the states by doing a lookup from the States table where the state relates to Australia)

Any ideas how I achieve this?

Thanks

Daryl