Oh...
Ok, I'll make it in steps:
1. Install Photoshop.
2. Open the Blizzard logo. Click Select > Color Range, select black colors. Now click the "Delete" button. Deselect by clicking somewhere on the picture with the mouse. Select everything (which is only the Text "Blizzard") and copy paste it onto a black picture (mono black, just black). Now you will have the text "Blizzard" and "black" in 2 layers.
3. Here comes the drawing part... Uf. Hmm, ok, so open the Fog picture. Copy paste it onto the Blizzard&Black image. Put it in between, Blizzard and "black". Now the fog should cover all the blackness except the Blizzard words.
4. Select a brush and reduce it's opacity. Start painting everything except around the Blizzard words. Slowly, remove all fog around Blizzard, some of the parts will be a little bit of ethereal fog which will add a cool look to it.
5. If you've painted it properly, it should look nice... Hm! You may encounter a problem with sizes and all, I mean the fog may be bigger than the "black" picture... which is the black layer.