please sir suggest me how will i install os android in the arm cortex m3
You can't. Android runs on A-profile cores, such as Cortex-A9 or Cortex-A15, not M-profile cores such as the Cortex-M3.
HTH, Pete
There have been hobby level ports of Linux to the Cortex M3 but no Linaro support. I'd recommend any number of other RTOSs for the M3 before attempting such a heavy kernel. As Peter stated, current versions of Android will run on Cortex-A (ARMv7) and some older versions of Android will run on ARM11 and ARM9 (ARMv6 and ARMv5) cores.