Hide/show date fields based on a checkbox value (yes/no) in a new or existing calendar item

Hi,

We are using sharepoint services 3.0.

I would like to ask, how I can hide/show the date fields below based on the checkbox value (yes/no) in a new or existing calendar item.

"Distribute Reports" (checkbox) - yes/no

"Reporting Start Date" (date_field)

"Reporting End Date" (date_field)

If the checkbox is checked (yes) the date fields should be visible.

If the checkbox is unchecked (no) the date fields should be hidden.

I believe I should change NewForm.aspx and EditForm.aspx.

Please, help me with the javascript.