I have had more time to look at the pilot version of the Glow portal. I must stress that these are entirely my own opinions. Given that Sharepoint was the starting point, the Glow team have tidied it up well but the underlying program is still Sharepoint and, for anyone familiar with that, it is not an easy portal to get to grips with. It has huge functionality, just like other Microsoft products. Imagine having no experience or knowledge of databases and coming on MS Access for the first time. Many teachers I think will find Sharepoint that sort of experience.
There is more excellent comment and material here coming out of East Lothian
It means therefore that its introduction will take time and will have to be taken a step at a time. There will be no point in demonstrating more than a fraction of the features. I personally would start with using links on the log-on page to access reasonably familiar things, news items, the school bulletin etc. I might then offer discreet training on each of the areas, e.g. the Glow discussion groups, using the email system and the personal space, etc. This would let teachers book into training that they see themselves as ready to use, rather than learning about things long before they can see the need.