all that info is in a .pst-file (or some other local file) that isn't deleted by the uninstall. But to be sure you could make a backup of that information. Of course, when you really go to use the software in stead of just trying it, it's essential you make a regular backup so any time spent to find out how to do it, and how to restore the data, is well-spent.
It seems rather easy, in fact: http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=651624&SiteID=17
and especially the Office help at
Hope this helps.
I have Office 2007 beta 2, with the trial having expired. I plan on upgrading to Office 2007 Professional, but as I understand it I have to uninstall 2007 beta before I can do that. What will happen to my contacts for Outlook? How can I save/export/back-up those contacts (and notes, calendar, etc.)? Since the trial is expired the export and save options are no longer available.