The Android 1.6 SDK is now available for download. Many of the highlights are good for users and manufacturers, such as a Market update and support for CDMA hardware. What's good for users is good for developers. Also included is a new gestures framework and a tool for creating gestures, multi-lingual and accent text-to-speech, and better search capabilities.
The API changes list is relatively small; this is an incremental upgrade with some nice features, but not a sweeping change by any means.
The update is set to be on handsets as early as October, according to the release notes.