SkypeIn
If you are interested in having a standard-looking phone number that your correspondents can call to reach you, then you might want to consider SkypeIn. SkypeIn (see http://www.skype.com/products/skypein/) assigns a traditional phone number to your computer that can be called from traditional phones (landline and mobile). You will receive incoming calls via your computer, but you can use your regular telephone (as demonstrated in this article) to answer your incoming calls. SkypeIn is a paid service, and at the time of this article's writing, the cost for a SkypeIn number was $38/year (quite the bargain).