Okay, I'll have you start with Arceus and Palkia, I start with Tyranitar and Jolteon. There is a sandstorm immediately from Tyranitar's Ability.
First Turn: I have Jolteon use Thunder on Palkia, taking advantage of the type-disadvantage, and I will have Tyranitar use Rock Slide, which hits both of your Pokémon. I assume you will use Hydro Pump with Palkia on Tyranitar, and then use Calm Mind with Arceus. Jolteon, being the fastest on the field, strikes first, taking out at least 1/3 of Palkia's HP (could be more, depends on his Sp. Def.) I assume that Arceus goes next. This makes it much more of a b!tch to beat. Palkia goes next, taking easily 2/3 of Tyranitar's HP with Hydro Pump. Now Tyranitar uses Rock Slide, cutting Palkia's HP by another 1/4, and taking at least 1/6 of Arceus's HP (again, what are his stats at?). All lose about 30 HP from Sandstorm.
2nd Turn: Jolteon uses Thunder on Palkia again, taking another 1/3 of the HP (again could be more). Arceus uses Ice Beam on Tyranitar, taking him out. I send out Walrien. You have Palkia use Spacial Rend on Jolteon, at cutting his HP by to least 1/2 (Sp. Attack stats?). The Sandstorm subsides when Tyranitar faints.
3rd Turn: Jolteon uses Thunder on Palkia again, ending his reign. So you now send out your Attack Deoxys. Arceus uses Judgement on Walrien, which at least cuts the HP by 2/3 at least without a STAB (does Zap Plate give a STAB?). Walrien uses Blizzard, affecting both Arceus and Deoxys, cutting Arceus down to 1/3 of his total HP left, and taking Deoxys down by 1/4 at least (STATS?)
4th turn: Jolteon uses Thunder again, focusing on Arceus this time, trying to take down the Pokégod, cutting him down to 1/8 of his total HP. Arceus uses Judgement on Walrien again, taking him out. I send out Houndoom. Now Deoxys uses Focus Blast on Houndoom, originally intended to take out Walrien had he survived the second Judgement. This takes out about 1/3 of Houndoom's HP due to the lack of a STAB (although the Attack stats with Deoxys-A could make a difference, I need the info for an accurate battle analysis).
5th Turn: Jolteon uses Thunder on Arceus, taking the Pokégod out finally. Deoxys uses Psycho Boost on Jolteon, taking him out. I send out Dragonite. Houndoom uses Crunch on Deoxys, taking him down to barely 1/4 of his total HP, if that.
6th Turn: Deoxys uses Dark Pulse (I'll let it hit both Dragonite and Houndoom) it causes Dragonite to flinch. Houndoom then comes in with another Crunch, taking out the attacking alien.
Your team should have some more filler Pokémon in it, just so you can do more damage with your legendaries while the opponent is distracted with your peons, taking damage all the while.