Android :: Should I Use Service Or Local Thread ?

I have an application which requires networking service. I took on LWUIT4IO and adjusted it to my needs so now i have a network queue that can run one or more network threads.Now, my application is based on single root activity that spawns other child activities as needed (it's a reservation center for vacations, car rental etc.. each in it's own activity). The network is common to all and should be used by all activities. the network thread requires, basically, a callback to notify it's finished and return the result (input stream or byte array) .At first i thought that i should use a service instead of a singleton that will be started in the root activity(the service will also be started in the root activity), however working with a local service is problematic for me: 1. no callbacks which makes me use intents to encapsulate the request esponse in intents time consuming, also since there is not single point of listening (i have to use BroadcastReceivers)i have to add a calling class name or some other identifier so the sender of the request will know it's for him, i think this is also a waste of time and resources since i need only one listener.

i think i CAN use callbacks if i use Binder object to return local instance of my Service and then use the queuing method directly, this is problematic for me as acquiring Binder object is asynchronous and i need it 'on the spot' 3. I thought of using a static instance of the service and null it in onDestroy of the service, but if i use that way, i'm not so sure i need a service... 4. i saw a small answer in stackoverflow about inheriting application and putting whatever member you need there so when you use getApplication you get this instance and then you can retrieve whatever you want, is this even advisable ?