Microsoft is close to buying Internet phone company Skype, which could be announced as early as Tuesday sources say.

The acquisition, which sources told is valued at over $7 billion, would augment Microsoft's other communications and online services, like Microsoft Messenger, Communicator and MSN chat networks.

Negotiations were wrapping up Monday evening, and a deal could still fall apart, the people cautioned.

The deal would also be one of the more aggressive deals in the software company's history. It paid nearly $6 billion for advertising firm aQuantive in 2007 and eventually backed down from what would have been its largest acquisition -- a $48 billion unsolicited deal for Yahoo in 2009,

Neither Microsoft nor Skype would comment on the matter.