For this weekend we'll get some reading on the topic of requirements in Agile:

• Writing Good User Stories. Nice concept of INVESTing in user stories.
• Latest description of FDD process. Pay attention to step 2 'Building a Features List'. Apart from precise definition of what a feature is, it introduces an interesting idea of time-boxing for features: a feature should not take more than 2 weeks to implement; if that's not the case - break it down.
• Why I still use use cases. Alistair Cockburn on what can be wrong with user stories.
• Writing Complete User Stories. Nice guide on how to address often perceived problems with user stories.