Hi Alaa, I would highly recommend " Visual Basic 6: How to Program by Harvey Deitel and Deitel". Its an excellent reference book that can easily be dipped into if you need to launch straight into developing your own program, or worked through for a great understanding. It is a little old now but you can still pick up copies.
Incidentally there is now a package called "Gambas" which is a sort of open source visual basic type language that I highly recommend!