What are the best moves for typhlosion in Pokemon emerald

I would say fire blast, flamethrower, lava plume and blastburn. Although I think he can only learn blastburn in leafgreen because you already learn it from a lady.
 You need to take advantage of Typhlosion's Speed and Special Attack abilities. Fire Blast with 10 PP, Sunny Day, Earthquake and Thunderpunch to counter his weakness's. Make sure it has a Magnet.  
I would recommend to transport your Pokemon into heartgold/soulsilver and you could go to the move tutor and ask him for a special move (blast burn).
Usually, Typhlosion is a good Pokemon with any move as long as you train it well.

Hope it helps!!! XD