Lexcycle, the company behind Stanza, a popular eBook reader for the iPhone, just announced that it has been acquired by Amazon. Amazon, of course, also just released Kindle for iPhone, which is now one of the most popular mobile eBook readers. According to Lexcycle, the company does not plan to make any changes to the Stanza app or user experience because of this acquisition, and Lexcycle will continue its relationships with its content partners. Neither Stanza nor Amazon disclosed the price of the acquisition.

Stanza currently offers about 50,000 titles from partners like the Fictionwise eReader store (which is now owned by Barnes and Noble) and O'Reilly, and another 50,000 free books for sources like Project Gutenberg and Feedbooks. While Lexcycle's most well-known application is Stanza for the iPhone and iPod touch, the company also develops desktop readers for Windows and Mac, which Amazon currently doesn't offer.

It is also noteworthy that Stanza has been a proponent of open eBook standards like EPUB, while Amazon has always kept its system relatively closed. Indeed, just a few weeks ago, Lexcycle announced that it was working together with Adobe to develop an open standard for eBook catalogs, which would make it easier for smaller publishers to offer their books through applications like Stanza (or even the Kindle, if Amazon incorporated this standard).

Overall, this seems like a curious acquisition by Amazon. With the Kindle iPhone app, its hardware eBook reader and its content partners, Amazon could easily compete with Stanza. It will be interesting to see how Amazon will manage to bring the two teams together and what it plans to do with Stanza in the long run. We can only assume that Amazon won't be interested in developing and supporting two different eBook readers.