OK, try this.

Open up your favourite drawing program (I imagine this will typically be Photoshop or PSP). Start a new image, the same size (pixel wise) as your video composition. make sure the image starts with a transparent background. This is usually indicated by the fact that the drawing canvas is a cross-hatch of little grey and white squares.

This picture will be overlayed over your video. Draw on your MTV (type) logo in the corner you want it.

Import into Premiere and place on layer 2 so that it appears over the top of your video. The areas witht he logo on will display and the 'transparent' areas of your graphic will allow te video of layer 1 to show through.

haven't actually done this myself and don't have the s/w in front of me so nto sure what the best type of graphics format to use is. Probably best not to use JPG though. not only is it a 'lossy' format but I don;t think it preserves transparency either. If you've got all Adobe s/w I'd stick with a PSD, layered, format.