Yes. But you will be limited to making calls that can be terminated on the Internet and to services that are open to interconnectivity. If you want to call a friends that is set up to receive calls using GoogleTalk, MSN Messenger, and Yahoo! Messenger, you can use RingFree to do so without a service provider. There are other Voice over IM services and SIP services reachable directly via the RingFree dialer without the need for additional services. You can also make calls to friends using SIP URI, usually an email address such as feedback@rf.com (yes, you can call there on your RingFree dialer). 

 Easy. On the RingFree dialer on your iPhone, click the "abc@" key and the familiar iPhone keyboard will come up. Alternatively, just click on the address bar near the top of the dialer to get to the keyboard. Now enter the SIP URI you wish to dial, and click the "Done" key on the iPhone keyboard. Back on the RingFree dialer, click the "Call" key and, then click the "Call" button that pops up on the iPhone to confirm a call to the local RingFree server.

 Sure. From the RingFree dialer, make a SIP URI call to us by "dialing" test@rf.call. You should hear a longish message about RingFree, followed by the traditional tone to leave a voice mail message. You can then leave a message, wait for a second or two, and hear your message repeated back to you.   You've just completed an IP call over GSM, with no provider involved.

 On the RingFree dialer, dial your friend's GoogleTalk user name in the form of "user@gmail.com".

On the RingFree dialer, dial your friend's MSN Messenger user name in the form of "user@msn.com" or "user@hotmail.com". If your friend uses a different domain name for his or her MSN account, you won't be able to complete the call until we make some fixes to the dialer (they're coming soon).

  On the RingFree dialer, dial your friend's Yahoo user name in the form of "user@yahoo.com".

 FWD is a free SIP-to-SIP calling service that was once very popular among early VoIP users and is working hard to make a comeback. To call a friend on FWD using the RingFree dialer, dial "*323-FWDnumber".`

 You can't, at least not yet.

Skype is a closed door, closed-platform system that is controlled closely by the US-based auction company eBay and is not open to any kind of inter-service-communication. With Skype, you're on their system and their system only.  With the rise of open services such as GoogleTalk, MSN Messenger and Yahoo! Messenger, Skype's popularity has waned significantly over the past year. Still, it continues to retain a large number of users, particularly in Europe and Asia.

Skype claims that, as a closed service, it works better than the open platforms. But there is no documented evidence of this, and users of other services generally believe this claim to be highly dubious, particularly given recent outages that have left Skype customers without service for days. 

RingFree expects to have a Skype calling work-around in the near future. However, that work-around will likely require the installation of an additional applet on a RingFree customer's home computer in order to operate (Skype itself requires a constantly on computer for its use) .

In the meantime, convince your Skype friends to  install any of the compatible Voice over IM (Google Talk, MSN Messenger, or Yahoo! Messenger) applets on their computer to run alongside Skype.