Rather unintentionally, Google has just let the name of the next Android release slip. As expected, it's going to be called Jelly Bean and will carry the 4.1 version number.

The leaked information can currently be seen on the US Play Store when purchasing a Galaxy Nexus HSPA+ smartphone described as "soon the first phone with Android 4.1 Jell..." You get the idea.
Additionally, there's also an image showing just a bite of the visual changes present in Jelly Bean. That's a new wallpaper and a visually refreshed Google search bar on the homescreen. The picture is of low resolution, but still the changes are somewhat visible.
This further confirms that Jelly Bean will be a minor update to Ice Cream Sandwich and we should expect Key Lime Pie to be Android 5.0 and probably launch with a new Nexus smartphone in the winter? There's no doubt then that Google will show Jelly Bean in action at the Google I/O Conference on June 27.