You can get a very cheap landline phone number in any country you wish (usually around $2 / month). If someone calls that number, the calls will be secretly forwarded to your online voicemail, your online voip software (so that you can receive the call on your computer, with a headset connected), or to your local cell phone in whichever country you are. The costs are extremely cheap, and the caller doesn't notice anything, except maybe a not 100% optimum voice connection. A good service that I'm using is www.sonetel.com
If you want to call people abroad, even cheaper than Sonetel one of the 60 voip providers from here: http://calltariff.com/
. You can type in, to which country you wish to call, and Calltariff will show you which voip provider is the cheapest one. Some of them (f.ex. my favorite www.powervoip.com
) allow you even to call from your internet browser. To a cell phone in the Netherlands f.ex. for less than $0,01. And all of the listed providers work together with an app for your smartphone, called 'Mobilevoip' (http://www.mobilevoip.com/
). You can initiate calls from your phone via local mobile internet, via callback to your local phone number, or via call through if you have a flatrate.