Please add following features as discussed.
1) Membership registration via Facebook, Twitter Google+ and simple User name Password.
2) Custom marker adding. Members should be able to mark a location with an icon. Once marked this icon should be visible to others, both members and non members.
3) Send\receive data handling
4) Markers data handling
5) Server side - Web service needs to be created and it should be on my server.
Please do it on your server for now. After successful testing I'll give you my server login credentials.