How to edit images to have this kind of perspective without photoshop?

Need to put a few images like this together with screens inside the frame of an iPhone as shown in the picture.How to edit images to have this kind of perspective without photoshop

PIXLR: http://apps.pixlr.com/editor/
GIMP: http://www.gimp.org/....gimp.org/
PAINT.net: http://www.getpaint.net/