There are a series of keyboard shortcuts for quickly switching between Outlook views:
Mail Ctrl + 1
Calendar Ctrl + 2
Contacts Ctrl + 3
Tasks Ctrl + 4
Notes Ctrl + 5
Folder List Ctrl + 6
Shortcuts Ctrl + 7
Either the top row or number pad keys work.
In addition, there are these two shortcuts:
Ctrl + Shift + I Jump to Inbox
Ctrl + Shift + O Jump to Outbox