No. DropBox does not provide CalDAV display. It syncs actual files, but this won't help you with calendars. Google Calendar is a good way to go: several people have reported that it works well for them (though I believe it doesn't sync ToDos, only Events).
Ok - thank you both. I was just curious. Used to have a MobileMe account and having the sync ability was handy - not necessarily a must. Rooting around I pretty much came to the conclusion it wouldn't work thru Dropbox - had to ask and make sure.