Finding the Helix Fossil in "HeartGold"
You must use the Rock Smash ability on a boulder to find a fossil in either game. The Rock Smash ability can be purchased in Goldenrod City. The Helix Fossil is found randomly in the Ruins of Alph. Smash all boulders in the area to find one. Smashing a boulder can cause you to either find an item, such as a fossil, encounter a wild Rock Type Pokemon or nothing at all. There are multiple Helix Fossils in the Ruins of Alph in "Pokemon HeartGold."
Preparing the Trade
You must use a Pokemon to transfer the Helix Fossil from "Pokemon HeartGold" to "Pokemon SoulSilver." Items cannot be traded by themselves, however items can be given to a Pokemon to hold onto. When a Pokemon is traded to a different game, it retains its hold item. Before the trade, catch a low-level Pokemon you already have and give it the Helix Fossil as a hold item. This way you do not waste a valuable member of your team just to transfer the item.
Conducting a Trade
Visit the top floor of a Pokemon Center and talk to the woman behind the desk to conduct a trade. If you and your friend are trading over wi-fi, you must exchange Pal Pad codes. If you are conducting the trade while sitting in the same room, you do not need to exchange codes. However, you must both perform the same action at the same time in both games to sync up your Nintendo DS systems.
Fossil Pokemon
Once you have traded your Pokemon with the Helix Fossil from the other game, remove the item from the Pokemon. Fly to Pewter City and talk to the man inside the museum to revive the Helix Fossil into Omanyte. If you want to thank your friend for obtaining the Helix Fossil you can trade him a Pokemon holding a Dome Fossil. The Dome Fossil is also found in the Ruins of Alph and is an exclusive fossil for "Pokemon SoulSilver"