writing a method that is accessible from any views as well as any controller

HI guys where should i have to write the method that it is accessible
from any controller and any views. When i write the method in
application controller then it is accessible in controller only and
when i write it on application helper it is accessible on views only.
I even tried to write it as module in the lib and included in the
application controller, in that case it becomes inaccessible in views.

Thanks Perez. What i do now is that i write it in application helper
and include it in application controller.