I'm looking for instructions on how to create a roll up calendar. Currently we have 6 calendars (one for each project) but wish to roll up all the events in these 6 to one master calendar in MOSS 2007 for the boss's to see. Can someone point me in the right direction. If there is a web part that already exists for this, I'd be interested in looking at that as well.
You can use the Content Query Web Part which allows you to summarise information from sites and sub-sites.
You can filter the result set to only show items from a specific site, list or even filter by columns or content type.
The Content Type would be most appropriate in this case, as each of your Calendars will be using the same content type.
Alternatively, if you want to "roll your own" I suggest looking into the SPSiteDataQuery class in the Microsoft.SharePoint object model. This allows you to do pretty much the same thing but from code.