DNS doesn't do port forwarding by itself. Why not run your server on the default mc port (25565), and then users don't have to specify it? Otherwise, they have to specify mc.1upclan.info:25575.
Anyway, I created mc.1upclan.info for you.
Note, minecraft.1upclan.info is still in existence (not sure who asked for it, possibly TitsMcGee back in the day, or Gautch). It points to 1upmc.dyndns.org currently. Can someone who has Minecraft tell me if that server is still up or not?
I read that Minecraft as of 1.3 supports DNS SRV Records; but I don't think Hostgator's DNS services support this; they claim they do, but I can't find anything in the control panel for them. It may be possible for Ron to put in a ticket to have that type of functionality enabled. If they did end up supporting it, our DNS server could provide the port to the client since Minecraft supports this now.