According to Eric Schmidt, Google Glass are about a "year-ish" away from getting a general market release. Glass was widely expected to be available sometime this year, though the new information from Schmidt during a BBC Radio 4 interview seems to suggest that this won't be the case.
Google is already releasing Explorer Editions of Glass to developers and they will get to play with them over the coming months, suggesting feedback as they go along. This feedback will then be used to improve the final version of glass before it hits the market.
He went on:
The fact of the matter is that we'll have to develop some new social etiquette. It's obviously not appropriate to wear these glasses in situations where recording is not correct. Companies like Google have a very important responsibility to keep your information safe but you have a responsibility as well which is to understand what you're doing, how you're doing it, and behave appropriately and also keep everything up to date.