1. ConvertC#2VB Offline tool.
http://www.kamalpatel.net/downloads/convertcsharp2vb_offline_tool.zip http://dghrp01/Download/convertcsharp2vb_offline_tool.zip
Kamalpatel.net
http://www.kamalpatel.net/ConvertCSharp2VB.aspx
2. C# to VB.NET Translator
http://authors.aspalliance.com/aldotnet/examples/translate.aspx
3. .NET decompiler
Salamander is a .NET decompiler that converts executable files (.EXE or .DLL) from Intermediate Language (IL, MSIL, CIL) binary format to high-level source codes, such as C#, managed C++, Visual Basic.NET, etc. For more than 8,000 classes that have been tested, Salamander always produces equivalent and recompilable codes that are remarkably close to the original source codes.
http://www.remotesoft.com/salamander/index.html