To find it, you'll need to:
1. Consult your owner's manual: This is the best resource for the exact location on your specific model.
2. Look for a small rubber hose: The drain is usually a small-diameter hose that exits the bottom of the vehicle's HVAC system. It might be tucked up fairly high, depending on the model.
3. Look near the passenger side firewall: This is the most common area for the drain.
4. Get underneath the vehicle: You'll likely need a jack and jack stands for safe access. Always use safety precautions when working under a vehicle.
If you can't locate it using these methods, a search online for "2006 Dodge Ram [your model] AC drain location" with images may help. You might also consider consulting a mechanic.