ECLiPSe has now been open-sourced under the Cisco-style Mozilla Public Licence 1.1. The ECLiPSe CLP project page is hosted at SourceForge, and has both binaries and sources. The first open source release is 5.10#25. Recent builds are available here.
If for some reason you need an older ECLiPSe version (5.9 and earlier), and you have an old academic ECLiPSe licence (issued by IC-Parc), then you can use it to download additional copies or components of these releases (in binary form) from this web site. To do so, please update your licence key here.