I'm just going into the round 2 area of this game and that I'm trying to level up some pokemon from my gba games to use in the game as I was using my teams in different events so I'm thinking of getting Mewtwo onto my yellow team but I'm not sure of moves to teach it as I only can think of is Psychic but what other moves would be good?
Some people have a tendency to put on the "boltbeam" combo (Thunderbolt and Ice Beam) as well as recover. This ensures that they can hit the maximum amount of types for good damage, while recover ensures it can stick about much longer by self-healing.
Where logic won't work - I will PAL Gamers unite - http://www.gamefaqs.com/boards/277-pal-gaming
Psychic and Recover are definite keepers. Amnesia is fantastic because it boosts his special by 2 stages. Substitute is great for its ability to block status. I use Blizzard over Ice Beam, but either one will work. My current moveset is Amnesia/Psychic/Blizzard/Recover, but I'm thinking about putting Sub over Blizzard because paralysis cripples Mewtwo.
I also go with Amnesia/Psychic/Blizzard/Recover. Amnesia guarantees that Psychic and Blizzard will do a lot of damage, even against things like Jynx and Slowbro (because Psychic usually destroys their Special). Paralysis is the only potentially-crippling status inflictor that can hurt Mewtwo, but even then it's still hard to put him down. Since most battles in Stadium only have 3 pokemon, a max-stat paralyzed Mewtwo can still destroy most teams before going down. It's that broken.
The thing to keep in mind with Mewtwo is that only a select few pokemon are faster, and not all of those can inflict paralysis. When you're pumping up Amnesia, just make sure you're against a pokemon that won't inflict Paralysis. Once that's done, most pokemon can be taken out in one or two hits, drastically reducing the likelihood that he'll be paralyzed. With those simple precautions, a Mewtwo with this moveset can tear through the game. Or, Rest instead of Recover gets rid of the Paralysis condition. Not that it really matters, since a Mewtwo with almost any intelligent set can tear through the game.
Alternatively, you could just forego caution and Amnesia-then-attack in front of any pokemon. Really, it's a Mewtwo. There's not much to worry about.
EDIT: In Stadium, Substitute/Amnesia/Psychic and Rest or Recover works really well too. Substitute protects your Mewtwo further, and an Amnesia-pumped Psychic will still be able to tear through most 3-poke teams. That's really only if you want to be extra-cautious. The computer in Stadium isn't good enough to handle a Mewtwo anyways, so it might just be a time-waster to use Substitute.