Rotating hourglass icon in status bar

[JMJMJM]

I have recently started using Outlook 2003. I noticed
that there is an icon in the shape of an hourglass in the
status bar. The icon continuously rotates. When right
clicked, it presents a menu with items Details... and
Cancel, both of which are greyed out.

Can someone tell me the purpose of the icon and how I
might be able to hide it?

Thanks,
Jim