add user to access public calendar

[Resi]

Hi
is it possible in Outlook 2003 to give permission to someone outside the
domain name to a public calendar?

at work we have recently started to use public calendars to book vehicle and
log our movement. this is working (mostly) fine.
however recently we have incorporated another project under our umbrella and
the person managing the project has a different e-mail address and website
domain than all of us. can I give her access to our public calendars?

would make life so much easier!
thanks