If you want to be involved with WLCG, please do bear in mind that the WLCG project is concerned with coordinating the efforts of large scientific computing centres and large university departments that have significant investments in computing and networking.
However there are ways to contribute to the LHC effort if you are not a large computing centre - read on!
Students and schools
If you wish to work on a project contributing to WLCG, you should contact a local university physics department that has some participation in the LHC physics program and discuss potential projects with them.
If you are based in the USA, there may be a local university that works with the Open Science Grid that can help you.
Individuals and volunteer computing
If you are an individual wishing to contribute home computer resources, you can become involved in the LHC@home project as part of the volunteer LHC computing program.
Don't forget there are hundreds of other scientific endeavours which also need volunteer computing help! See the e-Science City and BOINC for information on how to get involved with volunteer computing in many other scientific domains.