Check out the Nick website more often, create an account and play the games or watch the videos
Buy some of the Danny Phantom Seasons or cool merchandise either on eBay, Amazon, or just straight from Nickelodeon's website
You could also win some gifted Danny Phantom episodes from iTunes or just buy them yourself from the TV Show section of the iTunes store
If you're really interested in Butch Hartman's work then you should join his official website and talk about Danny Phantom, Fairly Odd Parents or TUFF Puppy. His website has been recently updated so it should be fun. Also check out his new Twitter account which he posted on his forum.
I'll post more links in the future, when I find fun and exciting websites.
And for those of you who are really interested in this cause the following may be important to you. Nickelodeon is a huge a company and to make it to turn it's head I'm going to need alot of help. I'm working 110% capacity to get this show back on the air but that might not be enough. I would really like it if people from around the country or even the globe (Because I am fluent in Spanish and I'm aware that Danny Phantom reached many parts of the Spanish speaking world) could help out for this cause. I need hand written letters, Nickelodeon should see handwritten letters. If you leave your contact information perhaps I can speak to you more personally and we can discuss other ways to get this show back in production. Please note that I will not require you to give me your real name but I do wish you give me some sort nickname that I can call you by. If you do decide to help this cause by giving me some contact info, I would like you to know that I do not share any information. Well, I hope you enjoyed the website and remember the easiest thing you can do and the most effective thing you can do, is increase the fan base. Make sure everyone you know understands the significance of, "Going Ghost!"
Sources: Pictures are from Nickelodeon's website and screen shots from the actual TV show Some information, including facts and numbers are from Wikipedia and any other written work is property of this website.