the CLI version is installed on the VNX and called nas_migrate  To find the GUI just go to support.emc.com - enter VNX File migration in the search box and then select support tools. I am currently checking if the one there is the latest version available.
Hello,  I've just finished reading the "Migrating data from an EMC Celerra or VNX array to a VNX2 using VNX replicator" whitepaper. I'd like to try using the file migration tool for an upcoming project. Problem is I can't seem to find it anywhere. I've tried looking for it on the support site and also through the partner delivery tools.
VNX File Migration Tool