I would recommend Easynews if you want a web interface to the binaries newsgroups. For retention Giganews can't be beat (>300 days at last count). Google Groups is great for regular text newsgroups.
So they don't let you have cameras in a secure environment, but WiFi is OK (and don't give me that whole wpa/wpa2 is secure enough - if it's government or important enough to warrant security that high - then it's important enough to warrant some class-a espionage)? Sounds like our government to me.
You may also want to look at some free, but not foss solutions. I know that Sun's Java Communications Suite is freely available and offers pretty much everything that exchange offers, including a pretty ajax-enabled web interface and an Outlook plugin so that it works just as if it were an Exchange server.
And then there's the foss solutions like Zimbra, etc.
It may not be opensourced yet, but Sun has released almost their entire enterprise stack for free for anyone to use, including their DSEE, with unlimited entries. It can synchronize with AD, and they have a good deployment planning guide for synchronizing with AD and there are guides all over the place regarding authenticating Windows off of LDAP servers.
"Why can't we ever attempt to solve a problem in this country without having a 'War' on it?" -- Rich Thomson, talk.politics.misc