Is this spam?
If you have to ask, it probably is.
The best definition of permission marketing used to be messages that were anticipated, personal and relevant. If this is going to be an asset of your organization (and it should be), let's take it to the next, easily measured level: would people miss it if it didn't arrive?
Once you have people looking forward to what you have to say, no more worries about spam. You've built an asset worth owning.