Unfortunately, if you use Outlook 2000 and publish a web calendar for any date after January 1, 2005, your calendar won't be correct — all dates in the calendar published to the web are a day early, possibly because the web publishing algorithm didn't take into account that 2004 was a leap year. Microsoft is aware of the issue and investigating, however I'm not expecting a hotfix for this issue for two reasons – Outlook 2000 is no longer supported and it only affects calendars published using the web publishing wizard, not the actual Outlook calendar.
Newer versions of Outlook are not affected and if upgrading is not possible, you'll need to use a Word template that pulls calendar data from Outlook then save it as an HTML file. These calendar templates are generally better for printing calendars and allow customizations such as pictures and coloring dates and make nice web calendars.
See Outlook 2000: Dates are Wrong When Publishing the Calendar for links to the Word templates.
Published December 15, 2004. Last updated on May 30, 2013.