If you have 2 gameboy colors, advances, or pockets and a link cable for gameboy color or pocket.
crystal,yellow,red and blue
I don't think so, because Yellow is first generation, and Gold is 2nd. They can link together, but in a limited access as Yellow doesn't have all the Pokemon in Gold. You might have more functionality if you completed the game or catched all the Pokemon in your pokedex, but I'm not 100% sure.
with a link cable
yes you can transfer a egg by link cable in the versions gold/silver/crystal. but u cant trade eggs to red/blue/yellow/green.
One can trade in Pokemon Yellow via link cable. Two Gameboy consoles can be connected via link cable and Pokemon can be traded across Pokemon Blue, Red, or Yellow.
You cannot get an umbreon on Pokemon Yellow as they were only introduced in Pokemon Silver and Gold and from then on. You can only get Vaporeon, Jolteon, and Flareon on Yellow.
you have to get a life!!
I say gold
No.
The Yellow Forest route on the Pokewalker? Pikachu. Only Pikachu.
You must trade with yellow or blue; there is no national dex in Pokemon red, blue, yellow, gold, silver, or crystal versions. If you don't have a trading link, buy one off of EBay or something, because it is not sold now, i think.
join the game colour link cable between the two game boys (it doesn't matter what type of game boy it is but the link cable has to be a game boy colour link cable). Then in gold go to the time machine upstairs in the Pokemon center all the way to the right. then enter the trade room in yellow.