getting bitcoin address of blk*.dat files
First, note that the scriptSig on the genesis block was before addresses were used. The scriptSig there is called p2pk, or pay-to-pub-key. Addresses (the kind starting with a 1) are actually p2pkh, or pay-to-pub-key-hash. You can convert one to the other fairly easily and that's what's going on here.

The actual scriptSig can be parsed like so:

41 = number of bytes in hex of the element (65 bytes)
04...5f = public key
ac = OP_CHECKSIG


Plug in 04...5f into the Public ECDSA key at http://gobittest.appspot.com/Address and you'll see that the address does indeed match.