Skype International and Boingo Wireless have announced a partnership that will allow users to access Skype's VoIP (voice over internet protocol) technology from 18,000 Wi-Fi hot spots worldwide.

Available in public places such as coffee shops, book stores and hotels, Skype Zones powered by Boingo are geared not only toward business travellers and students, but also any wireless user in search of cheap international calling, a Skype spokesperson says.

Skype Zones offer VoIP users unlimited access to Boingo's public broadband for $8 (£4.50) per month. Also, infrequent users can pay $3 (£1.70) for a two-hour connection.

The version of the product currently available on Skype's website is a beta, however, and the company pointed out that prices and availability may change before the final version is released.

Luxembourg-based Skype International's existing offers will remain. At the moment the company gives users the ability to make free calls to other Skype users over the internet and also allows its customers to make VoIP calls to traditional fixed line and mobile networks at significantly reduced rates.

The VoIP industry is young but growing rapidly. Skype claimed that as of 22 June its 43 million user base is growing by 140,000 users a day.

Companies such as Skype, Boingo and competitor Broadreach Networks are seeking to capitalise on developing mobile technology such as mobile internet telephony in order to keep adding users.

Though the largest percentage of the Boingo hot spots that are used by this product are located in the US, many are spread across 35 other countries, according to the company's website .