Internet based voice call with skype user

[nostar]

Is there any way to use my OBi100 / google voice setup to make or receive a call to/from a skype user, or some other software perhaps?  Basically I'm looking to talk to someone over the internet from their PC.  We are both linux users, so the software on his end would need to be something generic.  He does have a gmail account, if that helps.

[nostar]

It looks like what I want will work good with sip.  The Ekiga program can make and receive sip calls.  I see info on how to make an sip call with the obi100, but do I have an sip address for it already, or can I make one in order to receive a call from the ekiga user?

[QBZappy]

nostar,

If your friend can use GTALK on linux that should be enough to call your local OBi using a pc.