In other words, the door is wide open for tight-budgeted small businesses, and Sklype is aiming straight at them.

Skype's vice president of global market marketing, Saul Klein, told InfoWorld the aim of Skype for Business was the "neglected" small office with between one and 10 people.

"[We want to] be the champion of micro-business," Klein said.

The business opportunity is huge, analysts say. Such hosted VOIP services for business are expected to be worth $785 million in 2009, up from $233 million last year, according to the Yankee Group.

Rivals are not standing still. AOL has said it will offer a product with its upgrade of Instant Messenger this year that will be aimed at small business. Yahoo and Microsoft struck a deal last year to work together on IM for Microsoft's Live Communications Server.