Thanks for doing the tutorial!
A couple of comments -
o) PHP as CGI seems to be working fine for me. [Hadn't seen that recommendation before I installed.]
o) The "chmod -R 755" may have been needed at one point, but I skipped that step with apparently no ill effects. [Have a predisposition to being conservative in file permissions and since many of the files didn't need x access, I tried without the chmod and went from there.]
o) After creating a new calendar file with Sunbird or Apple's iCal, the file has permission 640 and it apparently needs to be 644. The only way I've found around that is to turn off WebDAV in the directory, "chmod 644 newfile.ics", and then change back to WebDAV. Since this problem apparently comes from the client and I don't think there are any configuration options on WebDAV, I can't find where I might have misconfigured something. Or is it just that, as a WebDAV newbie, I'm completely missing something obvious? [I realize this isn't a PHPiCalendar problem, but was wondering if it might be Dreamhost specific or otherwise need a note in the instructions.]
PHPiCalendar was pretty straightforward to install (and would have been even easier with your tutorial!) and seems better than the webcalendar that the DH folks just added to the one-click install menu.