Although this Australian case study is of a local government customer, rather than an education one, I think that it's relevant because there are so many aspects of a council that match education institutions:
Pretty much all of those issues are identical for education institutions.
What the council have done is replace an ageing conventional telephone system with a Microsoft Lync unified communication system, linking telephone, video and audio conferencing, and their existing email system in Exchange. But it wasn't something that they could rush into. According to David Carroll, the Infrastructure and Operations Team Leader for Adelaide City Council:
Many education customers already have Lync licences included within their EES agreements, or can get some of the capabilities within the free Office 365 for education service (although the telephony bit definitely isn't included free!). So the cost of deploying a system similar to Adelaide's won't be prohibitive – and the savings that can be made by switching from a PABX are a big incentive (Adelaide report that their annual phone costs are now a quarter of what they used to be):
The list of benefits that the council report in the case study are impressive (you'll need to read the case study for the details behind each of these bullet points):
Read the full Adelaide City Council Lync case study
(If you want to find Lync partners in Australia, then Microsoft Pinpoint is the easiest way)