I have to change background of my company's logo so that it will blend in any banner or background, which can be done by using "MAGIC ERASER" tool of Photoshop. But now i don't have photoshop i have GIMP , please any one can tell me how to do this.
Finally, there is another method which involves using the lasso select tool to select a general area and then creating and editing a layer mask to precisely define the selection before copying the selected area from the background image.
See tutorial here: http://photo-info.co.nz/articles/removing-image-backgrounds-gimp
The lasso+layer mask method is handy if you're trying to isolate an object from a photo, or if the background has a lot of colours, complex patterns or uses gradients.
Depending on your needs, one of these methods should work.