As you might know, cellular operators don't like VoIP providers like Skype so much, as they see their earnings twindle. Officially they claim that their networks will be overloaded but this is rubbish, as VoIP doesn't consume so much bandwidth. In this country, you can still earn a lot with overseas calls from mobiles.
Here is the situation in Germany right now; You have to distinguish between actually blocking the ports, not allowing it in their T&Cs and accepting it anyway.
Telekom (and its MVNOs): hates Skype and actively blocks it, except on a few tariffs open for VoIP and a surcharge
Vodafone (and its MVNOs): dislikes Skype and bans it in their T&Cs of most tariffs, but with no consequences
Telefónica (O2 and E-Plus and its MVNOs): allows VoIP right now. Some of its MVNOs may also ban it in their T&Cs like e.g. Simyo, but with no consequences.
So you have to choose between doing what is forbidden or what you are not supposed to do. But stay away from Mother Telekom with VoIP. The same mother who runs T-Mobile US allowing Skype in your country. So you better misbehave
