String.InStr (gb)
Static Function InStr ( String As String, Pattern As String [ , From As Integer, Mode As Integer ] ) As Integer
Returns the position of the first occurrence of 
Pattern in 
String.
If 
From is specified, the search begins at the position 
From.
If the substring is not found, this function returns zero.
Mode can be set to 
gb.IgnoreCase for a case insensitive comparison.
This function returns the index of the found character, not its byte position.
Examples
PRINT String.InStr("Benoît", "t");; InStr("Benoît", "t")