Total inputs - total outputs = fees

For example:
http://blockchain.info/tx/1c7179f134e553df60e5f5bc2f6484e7c10ae04d04373d63e2fc86cb0f978295

1.69788468 in
1.44 + 0.25688468 = 1.69688468 out


1.69788468 - 1.69688468 = 0.001 fee