Supports .NET 3.5+, Silverlight 4, Windows Phone 8, Mono, MonoTouch, Mono for Android
Easy installation using NuGet for most .NET flavors
Supports strong naming using NuGe for most .NET flavors
Automatic XML and JSON deserialization
Supports custom serialization and deserialization via ISerializer and IDeserializer
Fuzzy element name matching (‘product_id’ in XML/JSON will match C# property named ‘ProductId’)
Automatic detection of type of content returned
GET, POST, PUT, HEAD, OPTIONS, DELETE supported
Other non-standard HTTP methods also supported
oAuth 1, oAuth 2, Basic, NTLM and Parameter-based Authenticators included
Supports custom authentication schemes via IAuthenticator
Multi-part form/file uploads
T4 Helper to generate C# classes from an XML document
http://github.com/restsharp/RestSharp or http://restsharp.org/
similar - http://www.nuget.org/packages/Microsoft.Net.Http/
origin - http://www.pipiscrew.com/?p=3523 net-restsharp