Sigma today made good on their promise to introduce lenses for the Sony E-mount (NEX) and for the m4/3 mount standard. The new small lenses, a 19mm f/2.8 and 30mm f/2.8 prime are designated DN (for digital neo). No price or availability date was given. A full set of known data about the lenses is posted in the Lens Database section of this site.
The sad thing is that neither lens really represents an option that people were demanding in m4/3, though the focal lengths match up a bit better for NEX users. Basically, m4/3 got a 38mm and 60mm prime, NEX got a 28mm and 45mm prime. In m4/3, we already have 20mm and 25mm primes that provide faster apertures and give us basically the same perspective as these new Sigmas. On NEX, we don't have a lot of prime lenses yet, so the two lenses are more welcome there, though basically this just gives us a slightly less prime wide than the 16mm Sony and a slightly faster and smaller prime (but without macro) than the 30mm Sony.
Thus, I'd have to say "disappointing" is the operative word here. Everyone was looking for Sigma to produce unique new lens options, and what we got doesn't deliver on the "unique" part at all. Still, it's a start, and one can hope that Sigma will look more closely at where the real demand is and produce some lenses we don't currently have options for.