Interesting new service, which allows your blog visitors to talk to you from anywhere in the world for the cost of a local/domestic call. I havent tried the service yet, but sounds exciting. You can also leave a voicemail if the person is not available.
From their website (some of these might be misleading) –
How jaxtr Works
When users add their jaxtr widget to a social networking profile or include a jaxtr link in their email signature file, they make it easy for the recipient to call them: the caller clicks on the link or widget, enters her own phone number and then her phone rings. After she picks up the phone, jaxtr connects her with the friend who sent the link, so the two can talk live using their existing wireless or landline phones. If the recipient is unavailable, the caller can leave a message; jaxtr then notifies the recipient that she received a voice mail and she can listen to it by logging into jaxtr. Callers can also opt to leave a voice mail message without ringing the phone of the person whose social networking page or blog they are visiting. In either case, the call is free to the caller, and they do not need to register for jaxtr.
When people make their first call by clicking on the link or jaxtr widget, jaxtr provides them with a special phone number in their own country, which they can use to call their jaxtr friend from any mobile or landline phone. This eliminates the need to be online or even use a computer to place the next call, and people can leverage their domestic calling plans to make free international calls to jaxtr users from their mobile phone. They don’t even have to be a jaxtr user to do so.
Since their phone numbers stay private, jaxtr users can choose which of their phones should ring when someone calls, or if calls should go to voice mail. Users receive email notifications of incoming voice mails and can then call back those people they want to speak with. Additionally, when jaxtr users change their work, home or mobile number, they can simply add or update their number on the jaxtr service; incoming calls then get routed to the phone of their choice. Jaxtr users can also block callers from reaching them or specify on a per-caller basis which callers can reach them live and which get routed to voice mail.
Anyone in the world can use jaxtr; jaxtr provides numbers that eliminate international calling charges in 29 countries. People can go to www.jaxtr.com and request an invitation to join the Beta. It is free to sign up. Users with active social networking profiles or blogs will receive preference for being selected to join the private Beta. Later this month, people will also be able to join based on the invitation of an existing jaxtr Beta user. Based on input from the private Beta, the company plans to expand operations rapidly and allow anyone to create and publish their own jaxtr link or widget. Jaxtr expects to earn revenue from power users, advertising and enhanced calling features.