The download web page, which contains the FME Server installation package, is located here: http://www.safe.com/support/support-resources/fme-downloads/fme-server/. The web page also includes download links to release and beta installation packages for various platforms.
To request a 60-day trial license of FME Server, visit http://www.safe.com/fme/fme-technology/fme-server/trial-download/.
You can also contact sales@safe.com to get access.