anywhere in the world ... for free.
I'm afraid that depends on whether you're connecting via computer, land line or mobile. While connecting via computer to computer is free, the latter two aren't free, nor are video/conference calls as far as I can tell. Skype is more than happy to sell you Skype credit, or a Skype phone number (a virtual phone number - although unavailable in some/many countries, it appears).
"CHECK RESTRICTIONS ON USE: In some countries there are restrictions on the use of the Software. It is your responsibility to ensure that you are legally allowed to use the Software where you are located."
Make sure you read their "Privacy Policy" (or "modification of your privacy policy"). Have no doubt they're tracking you (cookies and gifs "to improve performance" - remember that one?) and probably selling your info as well:
"In order to provide you with Skype products you have requested, Skype may sometimes, if necessary, share your personal and traffic data with Skype’s group companies, carriers, partner service providers and/or agents. For example the PSTN-VoIP gateway provider, WiFi access services providers, distributors of Skype software and/or Skype products, and/or the third party banking organizations or other providers of payment, email delivery, analytical services, customer support, or hosting services. Skype will always require these third parties to take appropriate organizational and technical measures to protect your personal data and traffic data and to observe the relevant legislation....
...If you are a member of the Skype Manager, detailed information about the activity on your Skype account including traffic data and details of your purchases and downloads may be accessed by your Skype Manager Administrator if you have agreed to such access. You can withdraw your agreement at any time by changing the settings on your account page on www.skype.com. If you provide personal data including your name and job title to be included in the Skype Manager directory, you acknowledge that such data may be viewed by other members of the Skype Manager.....
...If you leave a voicemail for another Skype user, your voicemail message may be transferred to a third party service provider (where the Skype contact you are trying to reach has signed up to receive voicemails by text message), and will be converted to text. The conversion process may in exceptional cases, require access by analysts. By using the voicemail product, you consent to the processing of your voicemail message by Skype and its service provider....
...Skype, Skype's local partner, or the operator or company facilitating your communication may provide personal data, communications content and/or traffic data to an appropriate judicial, law enforcement or government authority lawfully requesting such information. Skype will provide reasonable assistance and information to fulfill this request and you hereby consent to such disclosure....
...Information that is collected by or sent to Skype and/or Microsoft may be stored and processed in the United States or any other country in which Microsoft or its affiliates, subsidiaries, or service providers maintain facilities. In this regard, or for purposes of sharing or disclosing data in accordance with this article 4, Skype reserves the right to transfer information outside of your country. By using Skype software, Skype's websites or Skype products you consent to any such transfer of information outside of your country.... (U.S., E.U. Save Harbor Regs)....
...As Microsoft continues to develop its business, Microsoft might sell or buy subsidiaries or business units. In any such transactions in which Skype or substantially all of its assets are acquired by a third party, personal information of Skype users will generally be one of the transferred business assets. We reserve the right to include your personal information in any such transfer to a third party...."
They also have a "Fair Usage Policy" which states you can't use the service for financial gain. Apparently, that's their bailiwick only. It's for personal communication only, and they'll be checking your usage pattern (where, whom you're calling, how often and times).
There are also countries which block/ed Skype. I can't find an up to date list... anywhere. That bothers me. Seems like Skype should publish that.
A VPN site had a list:
http://provpnaccounts.com/List_of_countries_which_block_website_content_VOIP_Skype_including_countries_China_UAE_Oman_Syria_Turkey_Malaysia_and_the_continents_of_Asia_Caribbean_Africa_North_America_Europe_and_the_Middle_East-124-articles
but since they're trying to sell you their services, I'm not sure how accurate the list there is.
While it may be possible to use a VPN to connect to/in these countries, some VPN's have been blocked as well.
It bothers me that Skype doesn't specifically list countries to which connection is a problem up front, nor countries which block VPN's. If you remember, there are places where you couldn't use a Blackberry because their "Intelligence" officials couldn't listen in due to the VPN or encryption protocol RIM used.
Instead, Skype itself breaks it down country by country and you'll have to search each country individually (to gain membership numbers, probably)... Also, calling appears to differ depending on whether the other person is using Windows or Mac. I don't see anything special regarding Linux, etc.
Countries on the list I checked are reachable by Skype... but when you look at their rates for mobile/land line, they are extremely high... like Guyana - $0.38 (US) per minute.