It's hard to know for certain what you mean by "it looks different." There are many interpretations of this phrase, such as "the color scheme looks different" or "the layout looks different." However, I'm going to take a leap of faith and assume that you mean that OWA shows different appointments in the shared calendar than you see with Microsoft Outlook 2003.
If that is the case, then I would ask how your Microsoft Outlook 2003 is connected to Exchange Server. Are you on the LAN? Are you using Cached Exchange Mode or offline folders? If that is the case, then it is possible that your Microsoft Outlook is (or thinks it is) offline and has not synchronized with the Exchange server and you are not seeing a "real-time" view of the calendar. OWA on the other hand, should display the updated contents of the calendar.
I have same issue with a public folder calendar. I'm not using offline folders or cached mode. Do you have any other ideas as to why some appointments show in Microsoft Outlook, but not in OWA?
Do you have comments on this Ask the Expert Q&A? Let us know.
Related information from SearchExchange.com:
This was first published in February 2007