Aligned parallel corpora constitute a critical information resource for a great number of linguistic and technological endeavours. Automatic sentence alignment has reached a level whereby large parallel documents can be fully aligned with the aid of interactive post-editing tools. Word alignment systems have not yet reached the same level of performance, but are good enough to support full word alignment if embedded in an interactive system. In this paper the authors describe a system for fast and accurate word alignment under development at the Department of Computer and Science at the Linköping University, where the user can review and improve the output of an automatic system in an incremental phase.