The app is needed for all major smartphone OS (but to start, it's okay if you could only offer single operation systems).

We need an app that rewrites the dialed number by making an HTTP query.

This means:
- the app should start with a number pad to dial the number
- the app should be able to browse the address book/contacts
- the app should be able to browse a redial-list

And: If possible (I know that it's not possible on the iPhone) the app should listen for outgoing calls in the background, so every call the user makes e.g. from the native address book is also handled via this app.

Once the user dials a number, the app should

1. cancel this call
2. open a URL like http://www.my-server.com/dial?parameters=see&below
3. read out a new phone number from the output of the called URL
4. dial this number

So, e.g.: The user dials 88814 on his phone. The app asks our server via http, we respond 00491234588814 and the app dials this number. If step 3 fails, the app should try to dial the entered number (fallback).

Parameters added to the URL should be (if possible):
- the entered number, e.g. 88814
- the phone number of the user (and if possible the IMEI of the mobile device)
- the mobile network (e.g. "T-Mobile DE" or MCC/MNC) and if this is the users home network or if he's roaming
- the GPS position of the user
- a version-key of this app


Configuration menu:
This app is given to a closed user group (it's not a mainstream app), so there is no big configuration needed: An on/off-switch and an "exclude list" (numbers like 112 or network shortcodes like check-voicemail), that's all.

Toolbox-menu:
Beside from the dialpad/contact list/call list, there should be one item "Toolbox". The toolbox is only a browser window (or if this is easier: it could be a link that opens the browser) that shows some functions the user could force on our server.

Start/Stop of the application:
Everytime the app starts or is ended, the app should call another URL (www.my-server.com/start) with the same parameters to notify us about the status change. We should be able to send GUI-updates (language pack, background/intro-image) and configuration changes (exclude-list, see above) e.g. via XML to the app during startup process.

I do not only need the app, but also the (well documented) source code. Anyway (I don't have time to develop it myself), there will be ideas for forther releases.