I'm designing a carpool system (drivers can publish their routes and passengers can subscribe to them) with WebServices(axis2) and Android clients (ksoap2).

I have been having problems with the logical architecture of the system and I wondered if this architecture is fine.

And another question: for that architecture (if it is ok), how would be the packages structure?

I suppose something like that:

(In android)
package org.carpool.presentation
*All the activities here (and maybe mvc pattern)

(In the server)
package org.carpool.services
*Public interfaces (for example: register(User user), publishRoute(Route route) )

package org.carpool.domain
*Pojos (for example: User.java, Route.java, etc)

package org.carpool.persistence
*Dao Interface and implementation (jdbc or hibernate)