my tomato plants are out of control

Do I need to do anything to them besides support? or do I just let them grow?

I am a newbie, and tried one of those pallet gardens and now the tomato have taken over.

you can start by removing the "suckers" that should tame them some... But yes a good supportive cage or trellis would be good.

suckers would be the branches with no blooms? Im really a newbie?

Here is a video on removing the suckers as mentioned.

Thank you guys so much, glad I stumbled onto this site!

If you can upload a pic of your plant... sorry i did not elaborate on what a sucker was...

to the forum and gardening!
Please never feel ashamed of mistakes or embarrassed to ask questions here....we have all made many of the same mistakes and started with the same questions you have. Take your time using the search box and reading through the info on this site and we highly recommend reading the All New Square Foot Garden book if you haven't already.
What kind of tomatoes do you have....are they vining (indeterminate) or bush(determinate)? If they are a bush variety, then tomato cages or some sort of support will be needed. If they are vining and the whole pallet is tomatoes, then it may be good to put up trellis on 2 sides or an arch (cattle panel works well) over the pallet garden to secure the vines too....many vining tomatoes will get over 8ft tall if you let them.

Lemoine brought up a good question, determinate or indeterminates? You remove the suckers on the vining indeterminates, not the bushy determinates. Determinates need their suckers to produce their harvest since they are built to produce a flush of fruit all at about the same time, then they are pretty much done. Cages work very well for determinates.
It will tell on the package or tag when you get it, which it is.

I notice in the video he removed not only the suckers, but the branches on the lower portion of his plant. That's because you want good air circulation down there and you don't want your branches touching the ground which could mean disease spores spashing up on the plant. After you have about a foot of clean space on the bottom, then you remove the suckers from indeterminates only, not determinates, above that foot.
Suckers grow in the upside down armpit between the main stem and the side branches. Remove them all below your first fruiting branch.