NSMenu *infoMenu;
infoMenu = AUTORELEASE ([NSMenu new]);
[infoMenu addItemWithTitle: @"Info Panel..."
action: @selector (orderFrontStandardInfoPanel:)
keyEquivalent: @""];
[infoMenu addItemWithTitle: @"Help..."
action: @selector (orderFrontHelpPanel:)
keyEquivalent: @"?"];
Then, you create an item in the main menu for your info menu, but
instead of setting an action and a target for that item, you set the
infoMenu as the sub-menu corresponding to that item:
NSMenuItem *menuItem;
menuItem = [menu addItemWithTitle: @"Info..."
action: NULL
keyEquivalent: @""];
[menu setSubmenu: infoMenu forItem: menuItem];