For a more fun look at Harry Potter related news, check out Wizarding Wireless Network Online. It's the electronic Daily Prophet for the tech savvy wizard or witch. They even have a Gringott's Bank Currency converter. Hmmm so this shirt will cost me 6 Galleons, 11 Sickles, and 3 Knuts. Good deal. The converter works for Muggle English Pounds & Muggle US American Dollars. Plus, the same man behind WWNO is behind the Wizard News. The site is inclusive of news related to Harry Potter and Lord of the Rings, i.e. movies, the actors, the books.

Go preorder your copy now, then head on over to the official site for all of the DVD's features.
Cho Chang's World Forum.
Cho-World[dot]com Forum
HPFGU Portkey has a mailing list, but before you post check out their FAQ. I bet most of your questions can be answered from their FAQ alone.
There are some serious dedicated sites to the "relationships" of the characters of the HP world.
Crushes & Quidditch - A Harry Potter & Cho Chang site
Never Better - A site dedicated to the Ron Weasly & Hermione Granger relationship
Mixing Up Trouble - A Draco Malfoy & Hermione Granger site *yah right!!!!*
More dedicated Cho Chang sites - Cho Chang.com & there's also BoA - Could She Be?.