Unfortunately, there does not seem to be a programmatic way to increase the taskbar item sizes. However, you can click and drag the edge of the task bar up to increase the number of rows displayed. That will give more room for actual items to display. Of course, moving the mouse over the taskbar item will pop up a tool tip so you can see the whole string. Another alternative is to press ALT+TAB because the popup window will show more text about the individual items. Be sure to use ALT+SHIFT+TAB to move backwards in the list.
This was first published in February 2001