ha! you dont need to convert them at all.
just drop like they are, with their ac, saves, attacks and everything. if you need something more dangerous, just add universal monster rules for advancing them ie if the creature is a magical beast then use a d10 per hd and such, i just watched one creature and was a wyvern so;
Wyvern is a dragon and universal dragon rule are like this:
Dragon
A dragon is a reptile-like creature, usually winged, with magical or unusual abilities.
A dragon has the following features.
d12 Hit Die.
Base attack bonus equal to total Hit Dice (fast progression).
Good Fortitude, Reflex, and Will Saves.
Skill points equal to 6 + Int modifier (minimum 1) per Hit Die. The following are class skills for dragons: Appraise, Bluff, Climb, Craft, Diplomacy, Fly, Heal, Intimidate, Knowledge (all), Linguistics, Perception, Sense Motive, Spellcraft, Stealth, Survival, Swim, and Use Magic Device.
Traits: A dragon possesses the following traits (unless otherwise noted in a creature’s entry).
Darkvision 60 feet and low-light vision.
Immunity to magic sleep effects and paralysis effects.
Proficient with its natural weapons only unless humanoid in form (or capable of assuming humanoid form), in which case proficient with all simple weapons and any weapons mentioned in its entry.
Proficient with no armor.
Dragons breathe, eat, and sleep.
