Here is a cool method from Ray to make the bottom labels on a chart to show vertically on the graph instead of horizontal.
Use the built in chart editor(CF_HOME\charting\webcharts.bat). And just change the XAxis/Style/Label/Orientation setting to Vertical.
The xml would look like this:
<frameChart>
<xAxis>
<labelStyle orientation="Vertical"/>
</xAxis>
</frameChart>
<xAxis>
<labelStyle orientation="Vertical"/>
</xAxis>
</frameChart>
Passing this onto chart, it looks like below:
Here is how the original horizontal one looks:
You also have options for Slanted, here is an example of Slanted:
