Skype has partnered with KDDI, Japan’s second largest telecommunications company. The deal aims at bringing internet telephony service on cell phones and broadband, fixed line and cable TV customers.

This is so far the biggest step Skype has take in Japan. KDDI is a massive telecommunications network with millions of consumers and businesses in reach, operating a nationwide fiber-to-the-home network, and has a grip on some of Japan’s prominent WiMax and cable TV businesses.

To start the partnership is the release of first to mobile units that are Skype capable. The ISO1 and ISO3 smartphones have an Android-based operating system, vastly expanding the Android integration on Skype’s part. The news comes shortly after Skype announced its support for Android. More Android- and Brew-based units will be released in 2011.

This is similar to the partnership of Skype and Verizon, a large U.S. carrier. The promotion includes an unlimited and free of charge Skype-to-Skype calls. After the promotion, calls will be routed to the telecomm’s voice network and charges will be incurred to them.

“We look forward to working closely with Skype to extend these benefits beyond mobile to broadband, fixed line and cable, and thereby maximize the satisfaction of our customers in every area of our business,” said Takashi Tanaka, senior vice president of KDDI, in a statement.

As Skype reaches for an IPO, the telecommunications service is aggressively seeking out strategic partnerships in order to increase access to its products. More recently this has included a partnership with Facebook, integrating contacts and news feeds from the social network into the Skype desktop app.