Microsoft promised Copy and Paste for first quarter 2011, and today they've started to make good on that promise. The update is rolling out to developer's first so that they can test their software and then it will roll out to consumers later. For developers interested in applying the update grab the Windows Phone Developer Tools January 2011 Update.
In the tools you will find updated reference assemblies and a new version of the Emulator that has copy and paste. Your existing applications do not need to be recompiled or changed to take advantage of this update. However, since this update will affect how a tectbox behaves you will want to ensure it doesn't interfere with any textbox interactions that you have designed. For example, if your textbox is inside of another control that accepts text input then the user could encounter difficulty when trying to select text in your application. If this occurs then you'll want to make an update to your application.
The copy and paste update is currently limited to being an update just to the text box. There isn't yet programmatic access to the clip board. But don't worry, that's coming later.
Tags: Windows Phone 7