you catch a magmar give it to hold then trade it and it will evolve into magmortar. to caatch a magmar go to floroma town then go up the route to your right when you get to a little opening there should be a little river on the left surf up it and you will get to the fuego iron works go to the litlle 3 x 3 patch of grass at the bottom left corner and yu should find a magmar at about level 30
Its on the upper rock path first item easy to spot
you have leafgreen inserted in the GBA slot and you catch a magby on route 227 or stark mountain you may have to catch more than one because some but not all have magarizers
porygon if you make it hold either dubious disk or up grade electabuzz if you make it hold a electrizer magmar magarizer hmmm im not to sure :P ----------------------------------------------------------------------------------------------------- Haunter evolves into Gengar if you trade it. What you can do with your friend is you can trade Haunters and then you both have Gengars. It works with Platinum, HeartGold, SoulSilver, Diamond, and Pearl as far as I know. I think it also works if you have Platinum and your friend has Pearl. I don't know yet. My friend and I are going to try it if she remembers. XP
It doesn't evlve at a certain level. You have to catch maggmy by putting Pokemon leaf green in you gameboy advance slot and then you search at I think it was kindle road and hopefully when he apears catch it and he might have a magmorizer. Here's why you need a magmoriser. So if you have a magmotar give it the magmorizer and trade it and it will evolve. Then trade back and you'll have one. So basicly any level you want it to evolve.