You cannot share the Eclipse installation directory or the workspace, but the projects themselves can be easily synchronized using a version control system such as cvs, svn, git, etc. I suppose you can store the contents of your project in the Dropbox folder (or a similar file system synchronization mechanism), and then just force update when you get on a machine using these projects, but I never tried it and was afraid that a human error might result in job loss or file corruption.
The key is that although the workspaces themselves cannot be separated, projects do not have to be physically located in the workspace folder on your file system. This is because the workspace is a logical container for projects, and not necessarily a physical container. When creating a project, you can specify an arbitrary file system location for the contents of the project. By default, only the location of the workspace is used. SO on each machine you will have a separate workspace that imports the project from any place where you synchronize them in your file system. Thus, the workspace is a tiny container that does not require much ongoing maintenance on each machine. I do this locally all the time - I have several workspaces on my machine, some of which include the same projects as others.
E-riz source share