Get a Calendar Icon at Far Side of Computer

Hi,

I've seen some computers with a calendar icon at the far
right side of the task bar (where the time is usually
sohwn). This calendar, when clicked on, will show the
current date and upcoming months.

I have Microsoft Outlook, but I'm not sure if this is a
separate program I can download or if I need to "turn on
a box" somewhere in XP.

Thanks for your help. This would be really handy!

J Lo