While Skype offers a wide range of voice features, you cannot port your existing phone number to Skype. There are some other options for users who want to receive land line or mobile phone calls on the Internet.
Skype Online Number
One option is to purchase a Skype online number. This is a subscription service that gives you a standard telephone number. People can contact you on Skype from any land line or mobile phone.
You can use your phone's forwarding feature to forward your calls to your Skype number. Remember, you are responsible for any forwarding rates from your phone service provider. This option will cost you more, but it is a solution if you are seeking for the convenience of having your phone calls come in to one number only.
There are Internet phone services similar to Skype that are exploring the ability to port your existing phone number to their services. Google Voice is one of the services looking into the option and hopes to offer it in the near future.