According to “two sources with direct knowledge of the discussions,” both Facebook and Google are weighing deals with popular video conferencing service Skype.

According to Reuters, both Facebook and Google have held discussions about forming joint ventures with Skype, and Facebook has at least talked about buying the company outright.  Since the discussions are still nascent,  there is no word from the sources on which way Facebook is leaning.

Skype is reported to have delayed its IPO, and Reuters says that a deal could be valued at $3 to $4 billion.  Other sources says Skype’s IPO will raise about $1 billion.  Though they wouldn’t rule out an IPO later in 2011, the sources are confident that Skype is already in “strategic discussions” with the companies.

As you may remember, this isn’t the first time that rumors have swirled that Facebook is courting Skype.

For Facebook, a deal with Skype seems like a logical prospect.  The company could add voice and video chat quickly and seamlessly to its service.  And of course, as we are all aware, Facebook has always had issues with their chat and direct messaging services.  Chat was much maligned when it first debuted for a host of connectivity problems.  Recent improvements have fixed some of the problems and Facebook has attempted to promote chat with more prominent indicators about friends’ online status.

Last year, Skype version 5.0 added a level of Facebook integration, allowing users to interact with Facebook directly through Skype.

Google’s interest is a little less intuitive.  Google already offers video chat through Gmail, iGoogle and orkut.  But that’s not to say that a partnership with Skype wouldn’t help Google Chat gain visibility.  Plus, not wanting Facebook to acquire Skype could be an strong enough reason for Google to act, points out BI.

Rumors are, of course, rumors.  But this one has been discussed for quite some time.  It’s not going to surprise anyone if one of these big players snatches up Skype in the near future.