how to link a library in eclipse c/c++ ide?

How can i link a library to ecllipse C/C++ IDE?I am using eclipse helios ​

You could write your own makefiles for the project.
or.. put the extra commandline options( -l<your_lib>) in the miscellaneous tab of the tool settings of the project.

there is a linker options page in the build settings area of the project properties. it includes options for library directories and additional libraries.