I'm attempting to override an element. The file structure is much like this:

templates/mytemplate/html/com_contact/contact/<files>

From the default_form.php, I wish to access another php file. Where will i keep that other file and what changes must i make towards the component view? I'm using Joomla 1.5.15.

Which kind of change? Could it be a big change you may make within the template override?