Ken Toyota, Nintendo Chief of public relations, spoke about many topics on Nintendo's plans. The information I found most interesting was what he had to say about the Nintendo Revolution (code name):

"E3 will be the starting point for the Revolution. [We haven't decided] whether we will show the real machine, videos, or unveil the concept. ... We want to receive some level of evaluation, but releasing too much information is also another issue. We don't have the slightest intention of making a machine that follows the same path as conventional game hardware. Right now, we are thinking of how we can accurately convey to people at E3 the different path that the Revolution will take and how it will change the way that games will be enjoyed."

There is no official name for the next-gen console from Nintendo, but one of the names I have heard is the Nintendo N5. On the other hand, according to Engadget, a source has leeked a name on Microsofts next console.

(Quote)Until Microsoft makes their official announcement on it, this one is still firmly in the rumor category, but we’ve gotten word from one of our trusted sources that Microsoft has pretty much settled on a name for the next Xbox: the Xbox 360 (let that sink in for a moment, because you’re probably going to be hearing it a lot for the next several years). Our source, who has worked on several projects involving the Xbox and the Xbox 360, has seen the proposed packaging and other design elements for the new console, and says that as of right now the console is being branded as the “Xbox 360.”(/Quote)

Revolution source: Gamespot