A great thing about Visual Basic is that it easily allows you to use standard windows controls. Once you start to get used to using these controls you will quickly find limitations. One such limitation is that they don't have standard save functionality. This is something that many times you will need to implement in order to retain data the user entered between sessions.
The source sample below adds some fake data to a list box. Normally this would be populated in some other way, probably by the end user of your application. The meat of the sample though is in how we open a file up, add all the items from the list and then save the file off.
In order to use this source code, simply create a new project. Add a list box to it and a command button. Double click on the command button and add the code below to its click event handler.
Obviously in a real world application you will want to do things a little more intelligently in regard to the file name, path, and such.
Note: The source for this was found at DreamVB which is no longer online.