Repost! We've got a repost here! See, nobody cares... ~Wayne Knight Jurassic Park meme
Adam Rifkin stashed this in Upvote! Downvote!
Photoshop makes it more difficult than it should be. Took me a while to figure out. I use Photoshop CS6, so here's how I do it:
So you've got your video frames to layers screen pulled up - timeline at the bottom and layers to the right. On the layers to the right, scroll up and select the second layer from the top. On the timeline, scroll to the left and select the second from the left. Let me add here that I'm not sure if this is all necessary, but it works so I don't mess with it. Okay, select your text tool and type in the gif. If I want to go word by word, I made a separate layer for each word. Maybe there's an easier way, but that's what I do.
After typing but before exiting out of the layer, reposition your text. I've found that this doesn't work as well after I've backed out of the frame. With the text still selected, click on Layer -> Layer Style -> Stroke. I usually set this to 3, 4, or 5. Makes the text readable. Once you've done that, click out of the layer. On the layers to the right, right-click on the text layer and select Copy Layer Style. Then on the timeline below, select the frame all the way to the left. Then go back to the layers to the right. Right-click and Paste Layer Style. This should apply the Stroke to all the frames.
Oh, I forgot to mention... Make sure your text frames are at the top on the Layers to the right, otherwise they might not show up. Last step... I think... is making the text appear where you want it. Select all the frames on the timeline below. If you don't know how to do this, you click on one side of the timeline, scroll to the other side, hold down Shift, and click the other side. Once all frames are selected, click the eye icon next to the text frame in Layers. This will remove the text from all frames in the timeline. Then in the timeline, select the frames where you want the text to appear and click the eye again.