I just upgraded from 2.3 to 2.6. and lost my permalink options.
Under >"Settings" >"Permalink" I get the following intro paragraph and then a blank page below. It doesn't list any settings/options for permalinks - and gives no examples - nothing... just a blank page under the paragraph.
Customize Permalink Structure
By default WordPress uses web URLs which have question marks and lots of numbers in them, however WordPress offers you the ability to create a custom URL structure for your permalinks and archives. This can improve the aesthetics, usability, and forward-compatibility of your links. A number of tags are available, and here are some examples to get you started.