I used the Hugin panorama photo stitcher and did some post-processing using GIMP. Hugin should be available in the repositories of your GNU/Linux distro, and it’s dead simple to use.
These are four pictures I took at the intersection of Grote Halstraat, Hoogstraat, and Gravenstraat in The Hague with a camera phone. I made sure that the pictures have enough overlap. (The Hugin tutorial recommends 20% to 30% overlap.)