Telcos offer as low as P2/min on international calls on the mobile phone. However, calls placed using the internet is a lot cheaper. Voice Over IP has been around since 1996. The first VOIP used the H.323 protocol instead of the more prevalent SIP protocol we use today.
The traditional telephone is slowly being replaced with broadband internet telephony or VOIP. During its initial stages, the "Internet Phone" had a very poor audio as compared to the traditional phone due to the lack of high speed or broadband internet. Today, all the issues that accompanied the "Internet Phone" in the early nineties have all been adressed.