VoIP is born from the growing Internet infrastructure, which has over the years seen significant improvements in both bandwidth and end-to-end latency. Merging VoIP technologies with telephony infrastructures is of particular interest since it significantly reduces the costs. In this project, we are making voice calls over Intranet available on a mobile phone using Bluetooth as the access protocol. Bluetooth was selected because it is increasingly available in mobile telephones. Most modern mobile phones with a focus on wirelessly sharing data between the device and a host PC come equipped with a Bluetooth adaptor. The project mainly consists of developing a Voiceover- Bluetooth (VoB) mobile application for Android phones and a PC application to enable voice calls over Intranet and Bluetooth connection. The mobile application connects to desktop application over BT to make and receive calls. The desktop application establish/receive call with/from other mobile/phone terminals over Intranet. When in range of a PC, a wireless Bluetooth connection to the IP network is made available to the mobile phone, offering the choice of connecting to a conventional mobile GSM network or to a lower-cost IP infrastructure. The vision for the future is to make the mobile phone’s operation fully transparent to the user by making both technologies completely interchangeable.