Google officially announced Android 2.2 "Froyo", claiming the new version offers significant speed boosts compared to the previous version, and that it features world's fastest mobile browser. You can read all the details at the Android blog.
Performance & speed: The new Dalvik JIT compiler in Android 2.2 delivers between a 2-5X performance improvement in CPU-bound code vs. Android 2.1 according to various benchmarks.
New enterprise capabilities: We’ve added Exchange capabilities such as account auto-discovery and calendar sync. Device policy management APIs allow developers to write applications that can control security features of the device such as the remote wipe, minimum password, lockscreen timeout etc.
Rich set of new APIs and services: New data backup APIs enable apps to participate in data backup and restore, allowing an application's last data to be restored when installed on a new or a reset device. Apps can utilize Android Cloud to Device Messaging to enable mobile alert, send to phone, and two-way push sync functionality. Developers can now declare whether their app should be installed on internal memory or an SD card. They can also let the system automatically determine the install location. On the native side, a new API now gives access to Skia bitmaps.
Additions to Android Market: Android Market provides Android Application Error Reports, a new bug reporting feature, giving developers access to crash and freeze reports from users. Developers will be able to access these reports via their account on the Android Market publisher website.