So I guess you don't have a WiFi network at home with broadband internet? That would be my first solution.
To do what you want though, some phones/devices have a hotspot option that allows the device to work as a WiFi hotspot. If your SII has that option then you could get the Tab on the internet that way by setting up the Tab to connect to the SII's hotspot (it would appear as a normal WiFi network).
However, many carriers (in the U.S. anyway) charge extra money for that ability so it may not be possible; or if it is, it may not be free.
Other idea:
If you have home internet and a PC or notebook connected to the internet that also has wireless capabilities then you may be able to start an ad-hoc WiFi connection between the PC and Tab. Whether that will get the Tab on the internet or not, I don't know.
If you have a computer with wireless but it
doesn't have internet available on it , then you may be able to tether the SII's internet to the PC (via USB) and then connect the PC & Tab together with an ad-hoc connection. But again, I don't know if ad-hoc connections pass internet through or just allow access between the two devices.