If you're worried about friends or family in Japan in light of Friday's devastating earthquake and tsunami, you can now make free phone calls thanks to several phone companies.

Time Warner Cable just announced that all direct dial calls placed using the Digital Home Phone service to Japan will be free through April 15, 2011. That includes both residential Digital Home Phone and Business Class Phone customers and will be retroactive for all calls starting on March 11, 2011.

AT&T, Sprint and Verizon Wireless are also offering free calls and text messages from the U.S. to Japan for all customers who receive a monthly bill. This will remain in effect for AT&T customers until March 31st. Verizon and Sprint customers will be able to call or text folks in Japan for free until April 10th.

AT&T landline customers can talk for free for up to an hour to family and friends in Japan through March 31st.