Nimbuzz is a very popular messenger and VOIP calling application, which is available on all major platforms and even has Symbian and Desktop clients. Great news is that with latest software update hitting Asha 501, it can be downloaded and installed on your Asha 501 as well. it will obviously be available for all other Asha 5XX devices too.
The application has a very intuitive UI and supports adding “Facebook” and “GTalk” contacts” in one chat window. So, you can just place calls or instantly message to any of your contacts from PC or mobile using Nimbuzz. It works on both WiFi and data. You can click here to install it on your Asha 501.