Receiving HTML e-mail in Outlook 2000 and Express 5

[Kay]

We have lots of different versions of Outlook floating
around our large office, and some old Windows 95 PCs have
only Outlook Express. Both Outlook 2000 and Outlook
Express 5 are getting the HTML messages I send (with
graphics, photos, etc.) in plain text format.

1. What, if anything, can be changed at the receiving end
to facilitate receiving HTML for both of these versions?

2. If #1 above is not possible, what do I need to do
differently at my end when sending? I have Outlook 2002.

Thanks!

Kay