The easiest way to access a majority of your Outlook calendar settings is by clicking on the "Calendar" button at the bottom of the left-side pane in Outlook 2010. The three sections covered are:
Sharing Your Calendar via Invite
Opening Another Calendar
Adjusting Calendar Permissions
1) In the top pane, click on "Share Calendar".
2) In the window that pops up you can select the people you want to share your calendar with, adjust what they can see from your calendar, and even request permission to view their calendar all in the same message.
Once you've finished customizing this window, click "Send" on the left-hand side.
1) In the top pane, click on "Open Calendar" and then select "From Address Book...".
2) In the window that pops up, you can search names of people and departments to try and find the calendar that you want. Once a name is selected and you click "OK", a request will be sent to that person to allow you to view their calendar, if it's required.
1) In the top pane, select "Calendar Permissions".
2) In the window that pops up, you can select a person's name that you're sharing your calendar with and adjust their permissions level. Once you have set their permissions, click "OK".