Yes there is one code you must have an egg first in your party and one another pokemon!
Is There A Code To Make Eggs Hatch Faster In Pokemon Heart Gold?
80890000 33310EC0
00000000 000000DC
10CB0000 00000000
00000000 000000DC
10CB0000 00000000
Not that I know of. But if you have a pokemon with the Flame Body ability in your party with an egg, it will hatch faster.