Solid first quarter for

First-quarter sales for online giant rose 18%, to $4.89 billion, up from $41.3 billion in the first quarter of 2008. Net income increased 24%, to $177 million, up from $143 million last year.

North America segment sales, representing the company’s U.S. and Canadian sites, reached $2.58 billion, up 21% from the first quarter of 2008. International segment sales, representing the Seattle-based company’s U.K., German, Japanese, French and Chinese sites, were $2.31 billion, up 15% from the first quarter of 2008.

The merchant got a boost from sales of the Kindle 2, an updated version of its wireless reading device. Launched in February, Kindle 2 boasts longer battery life, faster page turns, a crisper display, and seven times more storage.

The Kindle Store offers more than 270,000 books, including 104 of 112 New York Times Best Sellers, plus top U.S. and international newspapers and magazines. “We’re grateful and excited that Kindle sales have exceeded our most optimistic expectations,” Amazon founder/CEO Jeff Bezos said in a release.