You can use the Office Communications Server Deployment wizard to install the Communicator Web Access snap-in.
To install Communicator Web Access snap-in on a computer
Log on to the computer where you want to install the Communicator Web Access snap-in as a member of both the local Administrators group and the Domain Admins group.
On the Office Communications Server 2007 R2 installation media, double-click SetupSE.exe(if you are installing Standard Edition) or SetupEE.exe(if you are installing Enterprise Edition).
On the Office Communications Server 2007 R2 Deployment Wizardpage, click Administrative Tools.
On the License Agreementpage, click I accept the terms in the license agreement(required to proceed), and then click Next.