How can I have two windows of Outlook XP (windows) open at the same
time (one showing calendar and one showing Outlook email)?

Hi bartonsurfer,

Here you go -

Displaying the Calendar in a Separate Window:
"To open the calendar in its own window (separate from the Inbox, for
example), right click on the Calendar icon and select "Open in New
Window".  The calendar will display as one icon on the taskbar, the
Inbox as another."
http://www.uncc.edu/sysdev/HowTos/Outlook/quickly_moving_outlook_messages.htm

Office XP Tips: Fast Access to Key Files; Outlook Time-Savers
Use Word's Work menu and Outlook's right-click tricks. 
"Open in New Window. Say you're tooling around in your Inbox and you
want to check your calendar. If you click on your calendar in the
Outlook Bar or the Folder list, the calendar replaces your Inbox.
After you check your calendar, you need to return to your Inbox and
find your place again--but not if you right-click your calendar and
choose Open in New Window. When you do, Outlook opens a new window for
your calendar and you can toggle back and forth using the Windows
taskbar. This command is also great for checking e-mail in other
folders and for opening tasks and contacts."
http://yahoo.pcworld.com/yahoo/article/0,aid,82084,00.asp

I think that will do it but if you need further assistance, please
post a clarification request before closing/rating my answer.

Thank you,
hummer

Google Search Terms Used

outlook xp "open in new window" calendar

Thanks - that answered it perfectly!

Thank you, bartonsurfer, I'm glad to hear all is well. If you haven't
yet, click on the links to see more tips. Thanks, hummer