It depends a lot on the features you are using. A lot of stuff is pretty much the same as in 2.0. In fact, since 2.0 and 3.5 share the same runtime, you can build a site in Visual Studio 2008 and then run it on a 2.0 web server.
Things that are compatible include most of the controls (GridView, DetailsView, SqlDataSource and so on), security, configuration and programming in general.
However, you won't be able to use the features that are specific to .NET 3.5, including LINQ, integrated AJAX (you can still use the external Ajax implementation) and the new ListView control. These features require the presence of the 3.5 Framework.
Fortunately, you can use Visual Studio's Framework Targeting feature; by setting it to 2.0 Visual Studio doesn't show you 3.5 features.
All in all I think you could get a pretty good understanding of .NET 2.0 and 3.5 with this book, and still run most of it on your host's server. But you won't be able to use some of the new stuff you learn in your web environment.
Hopefully it's just a matter of time before more hosts start supporting 3.5.
Everyone is unique, except for me.
Author of Beginning ASP.NET 3.5 : in C# and VB
, ASP.NET 2.0 Instant Results
and Dreamweaver MX 2004
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