If you download the unlocked version of Skype and choose a calling option, they give the opportunity to add an "outbound" # option. Use the number associated with your galaxy tab, and when you make outbound Skype calls, it shows up as your galaxy tab number. I have not purchased the inbound number option, but it may give the option to verify it, and have it ring to Skype which would be sweet. This option also makes it obvious to someone you call from this number to text you back at it which will go to your messaging app. If someone wants to buy the inbound number and see if the option is there that would be awesome.
Edit
I just checked and a Skype in number is 18 for galaxy3 months. However, if you sign up for unlimited us and Canada calling for 3 a month, you get half off the Skype in number. So you get unlimited in and outbound for 6 a month.
Edit
I just checked and a Skype in number is 18 for galaxy3 months. However, if you sign up for unlimited us and Canada calling for 3 a month, you get half off the Skype in number. So you get unlimited in and outbound for 6 a month.