One of the nicest features within EFv4 (the next version of EF which will be also part of .NET 4) is the support for POCO classes and self-tracking Entities (entities which know how to do their own change tracking regardless of where our changes are done; really cool for n-tier scenario!!!).
In order to generate POCO classes and Self-tracked Entities, Microsoft plan to ship T4 Templates, which allow to completely replace EF code generation with custom code. Unluckily Visual Studio 2010 does not provide an out of the box T4 Template Editor.
The good news is that there are already 3rd party solutions available in order to edit T4 templates. Here the ones I found:
(you can download and install it using the new Extension Manager functionality of Visual Studio 2010. Extension Manager is available within the StartPage of VS2010)