How can i make a curve like in this pic?

or

In what program?

What program are you using?

edit Damn, Kristina beat me.

edit #2 For photoshop, when you use the text tool, at the top bar you should see something that looks like this:


Just press what is circled and then a box should appear allowing you to choose what you want.

If not for photoshop, then look around you program for something that says "warp text".

Hope this helps.

Not the words but the rainbow thing.

that person probably drew it that way probably using the pen tool

pen tool, curve tool and color fill.