How can you check the transimmision fluid on a 2006 toyota tacoma, does it have a dip stick?

Checking the "sealed" transmission behind the 4.0 is similar to checking a manual transmission. On the transmission housing under the truck, there is a fill plug on the top, check plug on the side, and drain plug on the bottom.
The transmission must be at the proper temperature, and when it is, remove the check plug and confirm that the fluid is at the edge of the hole.
But unless it is leaking, the amount of fluid will be the same as when you bought the truck unless the cooler in the radiator is leaking (check coolant for oil).
Toyota considers the sealed transmission to be a "lifetime" fluid, but the dealership will be happy to change your fluid if you would prefer to do so. I recommend every 100k unless you are towing.

Yes its on passenger side of truck up close to the fire wall