  Performing the first-principles calculations, we investigate the anisotropy
in the superconducting state of iron-based superconductors to gain an insight
into their potential applications. The anisotropy ratio $\gamma_\lambda$ of the
c-axis penetration depth to the ab-plane one is relatively small in BaFe2As2
and LiFeAs, i.e., $\gamma_\lambda \sim 3$, indicating that the transport
applications are promising in these superconductors. On the other hand, in
those having perovskite type blocking layers such as Sr2ScFePO3 we find a very
large value, $\gamma_\lambda \sim 200$, comparable to that in strongly
anisotropic high-Tc cuprate Bi2Sr2CaCu2O{8-\delta}. Thus, the intrinsic
Josephson junction stacks are expected to be formed along the c-axis, and novel
Josephson effects due to the multi-gap nature are also suggested in these
superconductors.
