Skype, which must fend off heightened competition following the launch of rival service Google Talk, has tasked Klein with overseeing global marketing for the company.
He will be responsible for managing the Skype brand, product marketing, partner marketing, integrated communications and research.
"With his global perspective, Saul is an ideal addition to Skype's leadership team and we are proud to welcome him as vice-president of marketing," Niklas Zennstrom, Skype chief executive and co-founder, said.
"Saul is an exceptionally strong leader and a consumer-focused, savvy marketing strategist. He will centre his efforts on consistently delivering the Skype experience to our fast-growing user base, while continuing to grow exciting new markets."
Skype has recently flagged its intention to up the ante on its marketing activity. Earlier this month, Skype appointed advertising agency Albion to produce a number of viral movies to promote the brand.
This summer Klein stepped back from his position as chief executive of Video Island to a non-executive role. He was replaced by former Dell executive Simon Calver.
On graduating from Cambridge, Klein founded The Electronic Telegraph and launched the paper's online fantasy football league. He also established Ogilvy & Mather Worldwide's digital media and e-branding business and later joined online technology firm Firefly, which was later bought by Microsoft.
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