What the Android IO session this May indicate:
1. Dalvik JIT may be in Android 2.2. or Android 2.3, Dalvik JIT IO session.
2. UI Enhancements may be coming to Android 2.2. UI IO session.
3. Multiple Android versions expected on devices at least util end of year. Targeting Android Versions IO session.
The precedent is to release a new android SDK version during the IO sessions. Last year android 1.5 was rushed out in April with two quick fixes afterwards and thus I think that Android 2.2 will be released right before the IO sessions.