View someone else's Outlook calendar

First off, this is assuming a few things.

1. You're using an Exchange server
2. Both you and the person you're trying to view the calendar of are on the same Exchange server
3. You have permissions to view the other person's calendar
4. You are using Outlook

If those four are all true, then you should be in luck. To view someone else's calendar should be fairly simple. Open Outlook, go to Calendar, then you should see some options on the left. One of those is "Open a Shared Calendar..." Click on that, search the directory and select the person you want to view the calendar of, then press Ok. To browse the directory, you can press the Name button. If the permissions are correct, the other person's calendar will open alongside yours within Outlook. You can toggle their calendar on or off by checking or unchecking the entry for them on the left of the window.

I'll be posting an entry on how to do this in Entourage soon as well