I HAVE A 2006 Saturn Vue AND IT WONT GO INTO.

There is either a problem with the gear shifter cable adjustment or the gear actuator, which the cable is attached to at the transmission, needs adjustment or it loose. Check to make sure it is not an internal problem if none of these issue are apparent by disconnecting the shifter so you can move the gear selector. You should be able to put it into get by hand and you will feel it go into each gear detent.
If it does nto take it to a tranmsission shop, not a regualr repair shop as they are not equipped to repair automatic tranmissions and usually send them out. The bad part of this is is the loss of money and time and psossible problems afterwards if they make the wrong diagnosis.

Also I would check for codes in the computer if the linkage was good. Also do you have the 4cyl or v6 engine?Yo only have 20,000 miles on the vue?

So have you checked for codes yet or checked the linkage yet?