  Temperature and magnetic field dependent measurements of the microwave
surface impedance of superconducting LaFeAsO$_{0.9}$F$_{0.1}$ (\Tc $\approx$
26K) reveal a very large upper critical field ($B_{\rm c2} \approx 56$T) and a
large value of the depinning frequency ($f_{0}\approx 6$GHz); together with an
upper limit for the effective London penetration depth, $\lambda_{\rm eff} \le
200 \rm nm$, our results indicate a strong similarity between this system and
the high-$T_{\rm c}$ superconducting cuprates.
