you should have gotten a call from prof.elm after you defeated the mahogany gym...
if you havent:
make sure you have 7 bagdes, if you dont have 7, go far east past ekrutik city to olivine and continue there until yu get that call from prof.elm
if you have:
do as coreyjm said, go to goldenrod radio station...
Join this site...http://s14.invisionfree.com/ChaoticRoleplayRealm/index.php?
and this one...http://gameknot.com/?rfr=diezombie...when you sign up the second one, where it says referals by, type in diezombie