I simply want to call methods of a local service from my activity. How can i do that ?
There is sample code for this right in the Service documentation, under "Local Service Sample":
http://developer.android.com/reference/android/app/Service.html#LocalServiceSample
Also for those people suggesting aidl -- if your service and client are all part of your own .apk and running in the same process (the default behavior), there is no need for aidl; it is just additional complexity that doesn't give you anything.