This is strange, the list-packages buffer shows \"available\" as the status for some packages that are actually installed. Shouldn\'t that column show \"install
I found it by chance: bring on the package list, find the package(s) you want to remove, and press 'D'. When you are done, press 'X' and it will remove the packages. It works exactly like when installing new packages, except that you replace the 'I' by 'D' (I think 'D' stands for 'delete').