J1.5:Menu parameter type
From Joomla! Documentation

Parameters have been superseded by form fields in Joomla! 1.6. You may want to use the corresponding Menu form field type. |
The menu parameter type provides a drop down list of the available menus from your Joomla site. If the parameter has a saved value this is selected when the page is first loaded. If not, the default value (if any) is selected.
The first option on the list is always '- Select Menu -' (which is a translatable string) and is given the value 0.
- type (mandatory) must be menu.
- name (mandatory) is the unique name of the parameter.
- label (mandatory) (translatable) is the descriptive title of the field.
- default (optional) is the default menu. Note that this is the name of the menu shown in the Type column on the Menu Manager screen and not the menu ID number.
- description (optional) (translatable) is text that will be shown as a tooltip when the user moves the mouse over the drop-down box.
Example XML parameter definition:
<param name="mymenu" type="menu" default="mainmenu" label="Select a menu" description="Select a menu" />