Where can you find Pokemon 486-499 and who are they?

First of all, it only goes up to 493... Unless you mean 489? I'll go on to 493, anyway. =]

#486. Regigigas. Once you've imported the 3 Regi's from your Ru/Sa/Em, then Regigigas can be found in the Snowpoint Temple.

#487. Giratina. Once you maneuver [spelling?] through turnback Cave along route 214, Giratina can be found deep in there.

#488. Cresselia. Go to Canalave City and talk to Sailor Eldrich, and he'll take you to Fullmoon Island. Once there, you have to pick up the Lunar Wing by talking to Cresselia. She'll fly off into the wild grasses of Sinnoh. You'll randomly encounter her, but you can track her down using your Marking Map app. On your Poketch.

#489. Manaphy. Trade your Manaphy Egg from Pokemon ranger and obtain the egg from a man in the Poke Mart. Hatch this egg, and you'll have a Manaphy.

#490. Phione. Breed your Manaphy with a Ditto, and you'll get an egg that contains Phione. But note, Phione cannot evolve into Manaphy.

#491. Darkrai, #492. Shaymin, #493. Arceus are all Event Pokemon. They require you having Mystery Event and going to a Nintendo Event. Using Mystery Event, you will have to obtain the: Membership Card [for Darkrai], Oak's Letter [for Shaymin], and Azura Flute [for Arceus]. Of course, you can always just cheat to get these pokemon.
#491. Darkrai. With the Membership Card, go to the hotel in Canalave City, and when you "wake up", take the item you find and show it to Sailor Eldrich, conveniently in town. He'll take you to Newmoon Island, which is where Darkrai is located.
#492. Shaymin. With the Oak's Letter, go to route 224, and at the end, there should be an extended route that leads to Shaymin.
#493. Arceus. With the Azura Flute, go to where you originally fought Darkrai on top of Mt. Coronet, in Spear Pillar. Use the Azura Flute and go up the stairs and fight Arceus [level 80, be prepared].

There are only 486 in this game, don't be silly.

485 is Heatran
486 is Regigigas
487 is Giratina
488 is cresselia
489 is Phione
490 is Manaphy
491 is Darkia
492 is Shaymin
493 is Arceus
494-499 is missingnos LOL

486)Regigigas- Snowpoint Temple with Regirock, Regice, and Registeel in party.
487)Giratina- Found in Turnback Cave
488)Cresselia- Grass of Sinnoh after meeting on Full Moon Island
489)Phione- Breed Manaphy and Ditto
490)Manaphy- Transfer Egg from Pokemon Ranger
491)Darkrai- Newmoon Island (Nintendo Event
492)Shaymin- Flower Paradise (Nintendo Event
493)Arceus- Hall of Orgin (Nintendo Event)

Espeon_dude, don't be stupid, look it up anywhere, there's more than 486 damn it, maybe, if you beat E4 go look for Giratina in turnbak cave.

In order they are Regigigas, you get it by going to the snowpoint temple with the Regis from a GBA version. Giratina I don't know where. Cresselia I don't know. Phione it looks like Manaphy and I don't know where. Manaphy get the egg from a Pokemon Ranger by connecting after you've completed "recover the precious egg!" Darkrai I don't know where. Shaymin I don't know. And last, but not least Arceus and I don't know. (I used an Action replay cheat so I don't know where to get most of them.)

Hey I have Bad egg it's #495 although I'm trying to hatch it if you can figure it out plz post.

All of you are wrong. I have proof here: http://www.serebii.net/blackwhite/pokemon.shtml