SoapUI - muito útil para developers - free

"soapUI is a free and open source desktop application for inspecting, invoking, developing, simulating/mocking and functional/load/compliance testing of web services over HTTP. soapUI Pro is an extended version with professional support and extended functionality."

http://www.soapui.org/

Acho que não é preciso dizer muito né?
É um UI (User interface) para testar e validar WS (WebServices)...

SandCastle - geração de documentação .Net

"Sandcastle produces accurate, MSDN style, comprehensive documentation by reflecting over the source assemblies and optionally integrating XML Documentation Comments.

Sandcastle has the following key features:

• Works with or without authored comments
• Supports Generics and .NET Framework 2.0
• Sandcastle has 2 main components (MrefBuilder and Build Assembler)
• MrefBuilder generates reflection xml file for Build Assembler
• Build Assembler includes syntax generation, transformation..etc
• Sandcastle is used internally to build .Net Framework documentation

"

SandCastle: http://www.microsoft.com/downloads/details.aspx?FamilyID=E82EA71D-DA89-42EE-A715-696E3A4873B2&displaylang=en

SandCastle Builder GUI: http://www.codeplex.com/SHFB