Media company Discovery Communications Inc has sued Amazon.com, accusing the online retailer’s Kindle of infringing its patent on electronic book technology.

The lawsuit, filed on Tuesday in U.S. District Court in Delaware, marks another blow for a closely watched gadget that has drawn fire from publishers that say Amazon is trying to avoid paying royalties.

The lawsuit claims that Amazon, in two versions of its Kindle, has infringed one or more of the claims on a patent that Discovery founder John Hendricks received in November 2007.

The patent deals with encryption technology for the distribution of digital books.

Microsoft Corp is set to publicly launch Internet Explorer 8 early on Thursday, the latest version of its market-dominating Web browser.

The application, an integral part of Microsoft’s eagerly awaited Windows 7 operating system, can be downloaded from Microsoft’s website from 9 a.m. Pacific time, free for people using licensed Microsoft operating systems.

IE8, as it is commonly referred to, has been in public beta testing for about a year, but Thursday’s launch marks its full public rollout.

Microsoft, the world’s largest software company, said IE8 will run with Windows Vista, its latest operating system, and also Windows XP, the previous version which some users still prefer over Vista.