Unicode support in VB6 is very limited. It was designed back when software wasn't truly internationalized and thus has problems rendering some character sets. Much of the IDE itself is ANSI only include menus, the property window etc. However, there are ways to get to Unicode with VB6 but it isn't always an easy route.
Some suggest wrapping controls in custom controls which support unicode, others have recommended books on designing with internationalization in mind. One such book is listed below...
Internationalization with Visual BasicIf you search on the net you can also find great websites that go into depth on the subject and can provide useful tips and code segments to demonstrate the process.
As for adding items to a listbox in 2008, you have to change the syntax a little from the old VB6 version
CODE
Listbox.Items.Add("text to add")
It was changed to this because now everything in .NET is an object so the listbox has a structure known as a collection called "items" for which each item is an object. You can add to the collection by calling the collection's add method and providing text or even an object. You can also use methods like count, remove etc.
Hopefully these answer your questions to your satisfaction. Enjoy!