You can public channel when you create the channel, but you have to wait for Roku to approve the channel. In my experience, the approval process is more concerned with graphics then function. I have alot of users on my private channel here on roku, and it's been running for I'd say at least a couple to three years maybe. But getting answers to how to fix or what needs to be fixed to get approved proved hopeless. so the public channel has sat for a long time as "in review" and never got published. meanwhile the private channel is doing great as always and not one end user complains about the appearance of it. Matter of fact, I've recieved comments about the direct publisher public channels looking "plain jane", "archaic"and "boring" in comparison to the private channel and public that is not approved.. My private channel and still waiting to be approved public channel are identical, use the same graphics and same xml files...
I have to say though going public is worth it, the DP channels have gotten more subscribers in 2 weeks then the private channel has in two years (or so)..
http://www.TVByDemand.com