For the tmobile galaxy s2 phone with the skyrocket since they are both 4.5" phones? I assume the AT&T dock sold for the s2 wouldn't fit as its 4.3 inches no?
If you mean the motorola lapdock then i'm pretty sure you can use it with an s2, but you won't get the full desktop. I think it works like hdmi, but don't quote me on it.