Windows 7 Client Retail Professional Edition English (x86 and x64) and Windows 7 Enterprise Edition English (x86 and x64) are available in MSDN Academic Alliance since August 6th for download by MSDN AA Administrators. Today (Aug 13), Windows 7 Client Retail Professional Edition English (x86 and x64) are available in ELMS (e-academy License Management System) that distributes the software to students. Enterprise editions of Windows 7 are for lab installs and so are not in ELMS.
See the snapshot of my ELMS download center with Windows 7 Professional (x86) highlighted below. Note that Windows 7 Professional is shown in the dropdown list as well as the box-shot below – either location is valid for obtaining the software.