if ur on winterboard, take this image "FST_BG.png" and put it in "yourthemename"/Folders/SpringBoard.app or "yourthemename"/Bundles/com.apple.springboard it will work either way. However this will only make the status bar transparent. If u want to make the wifi, signal bar, carrier logo, etc. dissapear as well, its gonna cost u some. The way the status bar works is there r three different ones (FST_BG, FSO_BG and Defualt_BG) FST for the lockscreen, FSO for the Spring baord and some apps, and Defualt for the other apps (its random which apps will use FSO or Defualt). But the thing is there are only two sets of images that go on the status bar (all those wifi, signal bar, etc things) and they are FSO and Default. So if u want the FST (lockscreen) status bar to have invisible images on it, u will have to make all the FSO_"imagename"'s invisible, and then u will have no images on the SB as well. I don't know how much u know about this stuff so it could be a little confusing for beginners. If u want to see how the images are structured, u can dl this
http://www.modmyi.com/forums/winterb...rything-2.html and look in the SpringBoard.app folder to see all the stock images that im talking aobut.