Many people think the only way to get unreleased neopets news is to have premium. But that it not true, in fact, you can't get unreleased news in premium, you only get to test the new unreleased games. Sucks huh? Just kidding. There's not a way to get all the unreleased news, but here are some ways you can get some unreleased news.
Unreleased Captions
Here's a common one =). You can see unreleased captions by doing this. First you have to go to the caption contest page (click here). Right click on the current caption contest image and click "properties". Copy the URL/Address. Paste it into the address bar. Where it says something like "caption_833.gif", I want you to change the number to the next number. So if mine was 833, I would change it to 834. Hopefully TNT has made the next caption image. Sometimes, they will have made the next one and the next and so on, so keep doing that until you get a 404 error xD. Those are all the unreleased captions!
Unreleased Games
As I said somewhere above, if you have premium you get to test out new games. But that's the only way I know of for how to play unreleased games. However, if you have premium or not, you can see games that are coming soon by going to the games room and scrolling down. Somewhere it should say "Coming Soon" and below it should be a game that is [obviously] coming soon and a preview picture ;).
Unreleased Pet Colors
Finding unreleased pet colors takes a little longer and some luck xDD. Basically what it is is a guess-and-check sort of thing. First, pick a neopet and get it's URL (right click >> properties). You can find the images here and clicking under "Pet, Petpet and Pb's" and then going to "Pets (all pets and colours)". Look at the right frame, there should be a color generator ;). Ok, get the URL of a non-basic colored neopet with the circle pose. Open a new window and paste the URL into your address bar. Now go back to the color generator. Get the URL of a different neopet with a color that can't be painted with the other neopet (circle pose). Paste it into the address bar. You will see that the URLs are similar, the only difference is the parts that are bold below:
http://images.neopets.com/pets/shoyru_brown_baby.gif
As you can probably tell, "shoyru" would be changed to a different pet and "brown" would be changed to a different color. Everything else stays the same. So on the first neopet you got the URL of, change the color to the color of the second neopet you got the URL of. Then press enter on your address bar. If you see the color of the second neopet URL you got and the pet of the first neopet URL you got, congrats! You just found an unreleased neopet. If you get a 404 error, sorry, neopets hasn't drew the pet yet xDD. Remember that this is mostly luck. It may take you 1 time to find an unreleased neopet, or 20. Good luck ;)