If your SFML is installed under a directory on the library path, you should just have to include the libraries under the linker in the project's settings. Under a project's properties, go to C/C++ Build -> Settings -> Tool Settings tab. Assuming you're using GCC, under GCC C++ Linker -> Libraries individual dependencies can be added to the list of Libraries. I usually add the following, in order, for SFML.
GL
GLEW
sfml-graphics
sfml-window
sfml-system
I tried a few quick searches but didn't find any decent documentation on this, but it's probably out there somewhere. I suggest getting familiar with the build settings in Eclipse CDT, such as adding include and library directories, setting compiler settings, etc. Also, if you obtained SFML from a repository, I'd check its version and consider compiling and installing the most recent version; there is a tutorial for this that makes it rather simple.
