Skype is a breakthrough product. It is a PC to PC voice communications system (it doesn't route through centralized nodes although it may use the PCs of other users on the network if there are firewall/NAT problems). It is also secured with strong encryption. This software was developed in Estonia and is unlikely to fall under governmental controls.
More about Skype's encryption:
When you call another Skype user your call is encrypted with strong encryption algorithms ensuring you privacy. In some cases your Skype communication may be routed via other users in the peer-to-peer network. Skype encryption protects you from potential eavesdropping from malicious users... Skype encryption ensures that no other party can eavesdrop on your call or read your instant messages. Skype uses AES (Advanced Encryption Standard) – also known as Rijndel – which is also used by U.S. Government organizations to protect sensitive, information. Skype uses 256-bit encryption, which has a total of 1.1 x 1077 possible keys, in order to actively encrypt the data in each Skype call or instant message. Skype uses 1536 to 2048 bit RSA to negotiate symmetric AES keys. User public keys are certified by Skype server at login.