Type your text, making sure it remains on it’s own separate layer.
Hold Cmd (PC: Ctrl) on your keyboard and click on the text layer, and it will load a selection around your text. Choose Select » Modify » Expand and set it to about 2 pixels (you can try different settings to get various effects). Click the Background layer and then click the New Layer icon to make a new layer under your text layer (see sample of layer palette below). Select the color you wish to use for the inner part of the outline and press Option+Delete (PC: Alt+Delete) to fill the selection with your foreground color.
Now, click the Background layer again, and then click the New Layer icon to make another layer under the layer you just made. Choose Select » Modify » Expand and set it to about 1 pixel (again, you can try other settings). Choose another color to be the external part of the outline and fill your selection with that color. Press Cmd+D (PC: Ctrl+D) to deselect.
If you’d like, you can continue by adding glow or shadow below the text, or any other effect that may be appropriate.