My advice to all administrators looking to set up the Unified Messaging server role in Exchange and/or the Office Communications Server is to create a fully functional test lab. Yes, you will need to learn some telephony terminology, but you can do it. It'll give you the confidence to really take advantage of the unified communications capabilities in Exchange 2010 when it come time for its deployment.
What Exchange 2010 brings to the unified messaging table
I already mentioned the voice mail preview, one of my favorite features in Exchange 2010's unified messaging capabilities. With speech-to-text translation, users can quickly read their voice mail and get the gist of the conversation. With Outlook 2010, if the speech-to-text engine didn't translate something clearly and you want to listen to the recording, you don't have to sit through the whole message. Instead, you can click directly into the message, at the line you want to hear, and Outlook 2010 will play the audio from that spot.
Note: The fax receiving features have changed between Exchange 2007 and 2010. In Exchange 2007, you can receive inbound faxes through the Unified Messaging server role, but the capability was just basic. In Exchange 2010, Microsoft worked with specialized fax vendors, so now a fax goes to the fax vendor, which then sends the fax as a TIFF attachment via e-mail to the user. Typically, fax vendors let users send faxes through e-mail, eliminating the need for a fax machine. Although the faxing workload is now handled elsewhere, Exchange 2010 authenticates the user with the vendor through a mailbox policy.
Exchange 2010 also lets users create their own call-answering rules, supports more languages for text-to-speech translation and speech recognition, improves name lookup from caller ID, and adds a message-waiting indicator.
Where are you in the world of unified communications? Have you implemented unified messaging in your organization? What pros and cons would you like to share with readers?