Microsoft Corp. is close to a deal to buy Internet phone company Skype Technologies SA for between $7 billion and $8 billion—the most aggressive move yet by Microsoft to play in the increasingly-converged worlds of communication, information and entertainment.

A deal could be announced as early as Tuesday, people familiar with the matter said, though they cautioned that negotiations aren't yet final and a deal could still fall apart. Including Skype's long-term debt, the total value of the deal is about $8.5 billion.

Representatives for Microsoft and Skype declined to comment.