Сабж зарелизили:

http://msdn.microsoft.com/en-us/devlabs/ee794896.aspx

Ссылки на скачку:
<b>[Для .NET 3.5 SP1]</b>
<b>[Для .NET 4 beta2]</b>
<b>[Для Silverliqht 3]</b>

А так же: <b>Reactive Extensions Team Blog</b>

Ура, товарищи, Erik Meijer strikes again!

Много вкуснятины:

The installer ships the following dlls:

System.CoreEx, api used by both System.Reactive and System.Interactive:

* Additional Action<,> and Func<,> types (for .NET 3.5 SP1 only, matches types in .NET 4)
* TimeInterval<T> & TimeStamped<T> adds time information to a value.
* IEvent<TEventArgs> wraps existing .NET event values.
* Notification<T> to materialize next/error/completed notifications.
* SynchronizationContexts provides access to common SynchronizationContexts.
* Unit, represents void for use in generics.
* BooleanSignal, a boolean state locking mechanism wrapping Semaphore.
* Semaphore adds the semaphore functionality to Silverlight 3.

System.Reactive, api related to IObservable & IObserver.

* IObservable<T> & IObserver<T>, the base interfaces for Reactive (lives in mscorlib.dll for .NET 4).
* Numerous Observable & Observer sequence operators:

o Standard LINQ operaturs such as: Select, Where, GroupBy, SelectMany
o combining operations such as Zip Repeat, Merge, Amb, Concat and StartWith.
o caching operations such as: Share, Memoize, MemoizeAll and Publish.
o creation operators such as: Return, Throw, Repeat and Generate.
o threading operators such as: Asynchronous, Synchronize, SubscribeOn, ObserveOn.
o exception handling operators such as: Catch, Finally, Retry and OnErrorResumeNext.
o evaluation operators such as: Run & Do.
o stream manipulation operators such as: Scan and Aggregate
o time based operators: Timestamp, Interval, Delay,
o remoting operator: Remotable

* Various Subjects, publish & subscribe (pub/sub) for Reactive with different caching policies.
* System.Joins.*, implements join-calculus on top of Rx.

System.Interactive, backport of Observable sequence operators that apply to IEnumerable as well.

* combining operations such as Zip (for .NET 3.5 SP1 and Silverlight 3), Repeat, Merge, Amb, Concat and StartWith.
* caching operations such as: Share, Memoize, MemoizeAll and Publish.
* creation operators such as: Return, Throw, Repeat and Generate.
* threading operators such as: Asynchronous & Synchronize.
* exception handling operators such as: Catch, Finally, Retry and OnErrorResumeNext.
* evaluation operators such as: Run & Do.
* stream manipulation operators such as: Scan.
* remoting operator: Remotable.