It became clear to me during my last blog post on the .NET landscape that it was going to grow into more than one post. 

Framework Versions

One fact that is important to note about the graphic in that post, and it was the catalyst for me making the drawing, is that the .NET 3.0 and .NET 3.5 frameworks do not supersede .NET 2.0 but augment it.

What I mean by this is if you were to look into your %WINDIR%\Microsoft.NET\Framework\v3.0 folder you do not get a new System.Data.Dll or System.Web.dll.  Instead you see the folders for:

• Windows Communication Foundation (Including Windows CardSpace)
• Windows Workflow Foundation
• Windows Presentation Foundation
  

If you look in your %WINDIR%\Microsoft.NET\Framework\v3.5.xxx\ (still beta at time of writing) the main thing to note here is a new csc.exe and vbc.exe.

So what do you get with .NET 3.5 & Visual Studio 2008 (codename "Orcas")?

• Managed AddIn Framework (System.AddIn & System.AddIn.Contract) ...also the CLR Add-In team blog.
  
• An AD/ADAM wrapper (System.DirectoryServices.AccountManagement)
• A WMI 2.0 Managed wrapper (System.Management.Instrumentation)
• Peer-to-Peer API's (System.Net.PeerToPeer & System.Net.PeerToPeer.Collaboration)
• In ASP.NET there is ASP.NET AJAX, asp:ListView, and the LinqDataSource. (System.Web.Extensions)
• Improvements to WCF and WF (System.ServiceModel.Web & System.WorkflowServices)
• ADO.NET Entity Framework (System.Data.Entity)
• New Crypto algorithms and support for Vista's Next-Gen Crypto, which replaces CryptoAPI. (System.Security)

Update:  Please also check out Daniel Moth's whole bunch Orcas posts, and his run-down of the new bits.

...and last but not least, the golden haired child, LINQ...

• LINQ to Xml (System.Xml.Linq) and LINQ to SQL (System.Data.Linq) ...also ScottGu's posts here, here and here are some of the best you'll find)
  

...and for everything that I have missed, or is not in the beta bits yet, grab the Orcas overview whitepaper.

What is .NET 3.5 going to do to 3.0?

It seems it has to do with Green Bits and Red Bits (source: Daniel Moth).  In other words, .NET 3.5 will also include SP1 for .NET 3.0 and SP1 for .NET 2.0.