I've just completed running the samples install and I see VB folders for most of the samples in C:\Users\Public\Documents\infragistics
Also, all of the help code examples is delivered in both C# and VB.
I know that the Showcases are only written in C# but most if not all other samples should have VB versions.
If there are particular code examples or samples you are not finding VB examples for please contact support and I'm sure they can help you find the files or code if it's available.
http://ko.infragistics.com/support/ask-for-help.aspx