How do I add items to the menu (in admin)

how do i add items in the menu in the admin interface
by the menu, i mean the bar that reads, “Write, manage, design, comment”
Im not sure what this bar is called, sorry.
Is there a plugin I can use to add links to it?

I want to use it to link to a different wordpress admin.
I know there is a wordpress admin switcher, but its horrid and shows saved passwords so its pointless!