Here is a short and sweet tutorial on creating an awesome fall / autumn landscape, complete with tree and falling leaves. This tutorial uses a mix of GIMP and Inkscape techniques, but should be easy to follow for just about everyone.
Here is an old list of 10 of the Best Inkscape Tutorials from back in 2009. All the links should work now, again.
Here is a neat tutorial showing how to create an urban design by layering different types of vector elements. In this tutorial, you first create a range of concentric circle stamps (or “brushes”), and layer them on top of different coloured cloud silhouettes. Finally, you create a whole bunch of swirls using the spiro curve and path effects.
Here is a another fun little tutorial from McKay Christensen showing how to create a neat texture effects using Inkscape. The awesome thing about this tutorial is that it is 100% scalable vector graphics (SVG), there is not a bitmap texture in sight! McKay achieves this by using SVG filters. To finish it off, he shows you how to put a rough paper texture over some text, and give it a drop shadow. This tutorial is a great introduction into the use of the filters dialog in inkscape.
This business card tutorial describes the procedure to create a stylish darker business card with a grunge bitmap texture background. While this tutorial is quite easy to follow, the author assumes a basic understanding of the inkscape interface (check out the official inkscape intro tutorial).
Here is another tutorial by Nicu that shows you in detail how to achieve the reflected surfaces effect. This tutorial covers how to achieve this in Inkscape first. Nicu then covers how to do it in the GIMP.
a tutorial that shows the technique to use a single gradient over multiple objects.