Personally, I would think the best way to dissemate those announcements is to create a weekly digest thread at a central location. Or better yet, make better use of the e-mail newsletters that I noticed that X10 has recently started to do (which is nothing more than ads that has little relevance to me, 98% of the time)
Purge all nonessential items and put only the top three most important facts/announcements/etc. maximum.
For example
Thread location: Central Announcements
Thread Title: For the week of March 30th, 2008
Content:
1) Servers X,Y,Z are undergoing planned maintenance. Expect downtime at A date and B time. Please see the general announcement thread here (clickable link) for specific details.
2) Users have mentioned issues with Servers V. We have addressed it and request that all members report any further issues and incidents at this thread (clickable link).
3) We are now accepting applications for mods in our community forum. Apply here (clickable link)
[Maybe a brief plug on paid plans here]