I don't have the book myself, but I believe it is called To
Touch Kindle a Soul, on chinuch. It contains, in the endnotes a reference to a letter written by Rav Moshe Feinstein zt'l, Rav Shach zt'l, and I believe R. Yaakov Kaminetsky zt'l which prohibited television. The Hebrew text was said to be included in the "Laws of Yichud" (by the same author as the nice grey three volume "39 Melachos" work I believe) but this is no longer in print.
Is anybody familiar with the contents and or know how to obtain a copy?
Is it more of a teshuvah or more of a kol koreh (from the book it sounded like it might be a teshuvah with sources etc.)