If UNHCR estimates are correct (reported by ITAR-TASS), the exodus of (primarily ethnically Uzbek) citizens is large - around 275,000. The logistical problem of ensuring the franchise for voters who are not in their home districts, and likely will not request absentee certificates, is tremendous. The scale of the violence, moreover, will deter citizens from participating. It is hard to imagine that a legitimate vote can be organized under conditions present in the south.
For more on the crisis, see posts at Registan.net, Eurasianet.org, Global Voices, as well as Kabar.kg for the official point of view.
On a personal note, I spent some time in Osh a few years ago and have several friends and colleagues in Kyrgyzstan. I want to extend my heartfelt concern to them and their families, as well as hope that peace and order will return soon to this lovely city.