Is there a difference between the two?
For i = 0 To Something.Length - 1 'do something Next For i = 0 To Something.Length - 1 'do something Next i
It is read-only:
You can specify a counter in the Next statement. This improves the readability of your program, especially if you have nested For loops. You must specify the same variable as in the corresponding For statement.
From http://msdn.microsoft.com/en-us/library/5z06z1kb.aspx
Nope. There is no difference. There is no difference even with nested loops, because nested loops cannot overlap.