New Microsoft job listings say that the company is looking for new hires "to help us bring [the] Skype experience on to the Web." Unfortunately, there are few details at the moment, but, as Windows Phone Sauce points out, the listings ask for applicants who have "real world experience developing HTML5 UI's." That doesn't necessarily mean it'll be an HTML5 web app, but it's certainly in the cards that it won't require Adobe Flash meaning it'll be able to run on more web browsers, including Safari on the iPhone and iPad.
Source: Windows Phone Sauce, Via The Verge