As Rusmas already stated, the Exodites do not have any rules for third edition. If you can get your hands on a 2nd Edition codex you can see what they used to be, but obviously those rules won't work directly with the current edition. It's at least a starting point for some house rules.
By far the most common Exodite army I've seen is proxied on the Saim Hann army list. Replace jetbikes with dino-riders and your pretty much in business. Best of all, since you are using an official army list, this make a tournament legal army that you can play anywhere.
Other conversions I've seen with the Saim Han list:
Teradactyles (sp?) for Vypers
Triceratops with a back mounted turret for War Walkers.
T-rex for a Wraithlord
The possibilities are endless... as long as you can find appropriatly scaled dino models.
