Create the text you want in photoshop, make sure it is the correct font/size and says what you want it to say. Then right click the layer and select rasterize type. Then, while layer is still selected, go to Edit>Transform>Warp. You should then see a grid overlaying your text, and you can take the bottom two corners and move it down to get the effect you want (or play with it in general to get it just right). If for whatever reason the grid isn't showing up you either need to make sure the little arch button is on (it is to the left of the cancel transition/apply transition buttons, and when you hover over it, it should say "switch between free transform and warp modes", OR you forgot to rasterize the type.