There is a direct bus, number 303, from San Salvador's eastern bus terminal that leaves every day at 2pm. An often faster method is to take any of the buses leaving from the eastern terminal heading for San Miguel and get off the bus at Mercedes Umaña from there buses leave every half an hour for BerlÃn up the volcano. The last bus up leaves at 6:30pm so try to arrive before then. Typically the bus takes an hour and a half from San Salvador to Mercedes and then another 30-45 minutes from Mercedes to BerlÃn.
If you are driving simply take the Pan American highway east towards San Miguel and turn right at the Mercedes intersection.
