Borders Group Inc said on Thursday it has reached a deal with the maker of the upcoming Alex electronic reader that will prominently feature the U.S. bookseller's e-bookstore on the device when the site is launched later this year.

The Alex e-reader will give the borders.com e-book site top billing, featuring it on its initial screen, a Borders spokeswoman told Reuters, though shoppers will be able to buy and read books from other sources on their Alex e-reader.

The Alex device, designed by Spring Design, uses Google Android software and will be launched on February 22 and sell for $399. It was unveiled at the Consumer Electronics Show in Las Vegas on Thursday.

In November, Spring Design sued Borders rival Barnes & Noble Inc, saying that company's Nook e-reader illegally copied Spring Design's dual screen design after the two discussed a possible partnership.

Rivals Amazon.com Inc and Barnes & Noble have both introduced their own e-readers.

Borders, the No. 2 bricks-and-mortar U.S. bookseller behind Barnes & Noble, last month said it would launch an e-books website by June that would be powered by Kobo Inc, a spin off of Canadian bookseller Indigo Books & Music Inc.

The Borders e-book store will offer two million titles.

Forrester Research estimates six million e-readers will be sold in the United States in 2010, bringing the number of e-readers in circulation to 10 million by the end of the year.

(Reporting by Phil Wahba; editing by Carol Bishopric)