I saw Zoro Movie Poster and I liked burning "Z" and I decded to amke a similar one using photoshop and here what I came out with:
1. Create a new document with black background, with the size you like (depending on your text size), I used 640 x 480 px.
2. Right the text, than duplicate layer and name it "fire". Hide the first layer we will use it later.
3. go to: Image> Rotate Convas> 90 CW.
4. than go to: filter> Stylize> Wind. Use these settings:

press ctrl+F to redo the effect, that will make flammes longer.
5. go to : Image> Rotate Convas> 90 CCW.
6. go to: Filter> distort> Ripple. choose between 100% and 150% .
7. go to: filter> Blur> gaussian blur. choose very samll value like 0.5 px.
8. Add Hue/Saturation Layer, use these settings:
9. Add Curves layer. Try to make a curve similar to this:
10. keep pressing on ctrl and click on the Hidden Layer, than go to layer A and press delete. Et voilą :
try diffrent font and setting, add more effect her and there and you can end up with very cool things.