This is a topic I suspect many people are interested in, and thinking about. There is also a lot of information out there. In terms of frequency, there seems to be no upper limit to what is good, but there is a diminishing return curve:

http://blog.hubspot.com/marketing/blogging-frequency-benchma...

And best time of day and day of week:

http://coschedule.com/blog/best-time-to-publish-a-blog-post/

Note that you can still tweet or facebook the blog after it is posted, and the tweet and facebook schedule may be more relevant since that is likely how people will find it.

The thing that I really wonder about: how do you find the time to produce something good. To write even once a week you have to find a topic, think about it, write about it and then edit it.