I reported last month that NSF was no longer allowing its graduate fellows to teach. According to an email I received earlier today, they are reconsidering the issue:
Each Fellow is expected to devote full time to advanced scientific study or work during tenure. However, because it is generally accepted that teaching or similar activity constitutes a valuable part of the education and training of many graduate students, a Fellow may undertake a reasonable amount of such activities, without NSF approval. It is expected that furtherance of the Fellow's educational objectives and the gain of substantive teaching or other experience, not service to the institution as such, will govern these activities. Compensation for such activities is permitted based on the affiliated institution’s policies and the general employment policies outlined in this document.
Each Fellow is expected to devote full time to advanced scientific study or work during tenure. However, because it is generally accepted that teaching or similar activity constitutes a valuable part of the education and training of many graduate students, a Fellow may undertake a reasonable amount of such activities, without NSF approval. It is expected that furtherance of the Fellow's educational objectives and the gain of substantive teaching or other experience, not service to the institution as such, will govern these activities. Compensation for such activities is permitted based on the affiliated institution’s policies and the general employment policies outlined in this document.