Source: http://www.engadget.com/2014/06/13/littlebits-midi-cv-usb/
Click 'em together, make some noise. Littlebits are like Lego for music nerds (like us). That's fun and all, but currently, once you've built your mini-modular synth creation, there isn't really much else you can do with it. That won't be the case for much longer though, as three new modules are coming along to spice things up.
We are raising the ceiling of complexity of what you can do with littleBits, adding wireless control, programmability, and now audio control to allow you to make sophisticated electronics in a fraction of the time and cost, allowing for whole new experiences. -- Ayah Bdeir (Founder, littleBits)
A new MIDI block lets you hook into music making software like Ableton or Logic, while the CV block means you can connect your littleBits to older/analog gear. If you just want to play with sound, a USB I/O module will let you pipe the littleBits' audio directly into your PC. No word on price, but expect to see them come to market in time for the (now noisier) holidays.
Source: littleBits