Most examples are actually in VBA, not VB.NET, though the two are very similar. Deepak linked to an article I wrote where I discuss the differences between the languages and program types that can be used with the SolidWorks API.
I would also encourage you to check out this blog post: 7 Mistakes New SolidWorks API Programmers Make
A few years back every example was in VBA so that was what I learned. Every year a larger percent of examples are written in both VB and C#. In the EPDM API it seems that most examples are written in VB.net and C#. Personally I wish I had learned C# instead of vb. Kudos to SW for including C#.
when you're familiar with C# you should have less problems to convert the code which is written in VB.NET or VBA to C#.
The structure will be almost the same just the methods will differ slightly.
I used to convert snippets from time to time and it worked fine for me.
You should get familiar with the online help that will help to get into it quickly.
I have written a couple of short programs in C# and can convert snippets and the individual methods. One of the things I have trouble with is that practically everything can be made public in VB and that is what I am used to (I know it is frowned on in C#) so in larger programs I have trouble writing with moving information around.