Designing Web Usability : The Practice of Simplicity. By Jacob Nielsen. Renowned Web usability guru Jakob Nielsen discusses design guidelines, use of multimedia and writing for the Web -- including his belief that text should be written concisely for "scanability."
Reporting and Writing : Basics for the 21st Century. By Christopher Scanlan. This may be the best journalism textbook out there. Packed with anecdotes and tips from practicing journalists, this book is useful to students and professionals. It includes a number of references to the Internet, useful links and a strong chapter on writing for the Web.