If you look in the folder where you unzipped Irrlicht, you'll see some specific .NET examples. If I remember correctly(I'm at school right now, so I don't have the files infront of me), the first two have been ported. Maybe 3. But you can also find the Irrlict.NET.dll in there too.
I forgot to answer your question, sorry. Uhh, not VB6, strictly speaking. But you can use it with any .NET language. So if you were to use VB.NET then you'd be fine.
But I don't think there have been any Irrlicht VB wrappers written, though I'm sure I could be mistaken.