There is a code for that using Edizon:
[18 Instant Egg (On)]
04000000 0134AB04 D503201F
04000000 0134AC54 D503201F
[19 Instant Egg (Off)]
04000000 0134AB04 7102D53F
04000000 0134AC54 540000C2
Using this with the Wild Pokemon are Shiny (Hold R) cheat make sure to hold R before you get the egg from the Day Care lady.
These two codes seem to be for instant egg hatching (whoever made the codes named them terribly, as the names are extremely misleading).