A single user license can be used in two machines provided you operate MyEclipse only on one machine at any given point of time. You can operate up to 2 instances of MyEclipse Enterprise Workbench on the same development machine at a time.
The recommended way of syncing projects between machines is a version control system like Git or SVN. If you do not want to use version control system then any solution that allows a set of folders to be synchronized would work. You can check in development related forums like stackoverflow.com for better suggestions from the developer community regarding sharing workspace between machines.
Hope this helps. Let us know if you have any questions.