Quoting from TLC because I need to run:

“Harry Potter and the Goblet of Fire” will be making it’s American network television debut on ABC Saturday April 26 at 8pm (ET). There are also rumors swirling regarding this too, claiming ABC may show new footage of Half-Blood Prince during the film. While this is very much unconfirmed, it is possible they will be airing some of the sneak peek excerpts of HBP as seen already on the OotP DVD, however at this point, we simply do not know what, if any, new preview will be aired. We are working to find out more about this,and will update with more when we can!