BrainMaps.org has recently implemented a new AJAX-enabled multiresolution image viewer.
What’s more, the multiresolution viewer has been released as the Brain Maps API.

The Brain Maps API lets you embed Brain Maps in your own web pages with JavaScript. Future versions will enable you to add overlays to brain maps (including markers and polylines) and display shadowed “info windows”. The Brain Maps API is a free service, available for any web site that is free to consumers.