I've also noticed online that several people have had to change their HTTPalias so they could get access to the site.  Is there a way to do that without going in to the site itself?  Since I can't seem to get access to it to add the Httpalias?

I was having the exact same problem.  I needed to run my DNN install from a different port than the standard port 80.  I did the exact same thing that you did (modify the PortalAlias table) and that fixed it for me as well.  Thanks for posting your solution!

I checked several time to make sure I was doing this on the test site, I even had the production site up and constantly testing while I was making any changes in case the site went down for any length of time.  This was done on a fresh install, but from what I've found, at least in my case, there is a bug in the system.  When I uncommented the UsePortNumber entry, it automatically defaulted to Port 80, regardless of what port I typed in to the browser.  In fact, the only way I could even see the front page of my site was to comment out that line and then type it in.  And if this is the case, then there's no reasonable way to actually get in to the site to add the HTTPAlias since I wouldn't be able to see that page with it defaulting to port 80 all the time, therefore the only way to fix this is to modify the entry directly in the PortAlias table in the database. 

I believe there needs to be way to specify either the port number in the webconfig if it's not port 80 or it needs to be modified to maintain the port number when navigating, or some way to get to the HTTPalias page to add that alternate port number URL.

On a side note, even once I got that alternate port number enteredin to the database directly, I still wasn't able to add other URLs with alternate port numbers, I constantly got "Invalid" as an error and, again, had to go in to the database directly to add them.