updated doxygen info

docs/sourcedocs.html

@@ -11,11 +11,22 @@
 <p>
 <A HREF="http://www.doxygen.org" target="_parent">Doxygen</A>
 is used to automatically
-produce cross-referenced documentation from the Mesa sources.
-This is not included in the normal Mesa distribution.
-Download Mesa from CVS if interested.
+produce cross-referenced documentation from the Mesa source code.
+</p>
+
+<p>
+The Doxygen configuration files and generated files are not included
+in the normal Mesa distribution (they're very large).
+To generate Doxygen documentation, download Mesa from CVS, change to
+the <code>doxygen</code> directory and run <code>make</code>.
 </P>
 
+<p>
+For an example of Doxygen usage in Mesa, see a recent source file
+such as <a href="http://webcvs.freedesktop.org/mesa/Mesa/src/mesa/main/bufferobj.c?view=markup" target="_parent">bufferobj.c</a>.
+</p>
+
+
 <P>
 If you're reading this page from your local copy of Mesa, and have
 run the doxygen scripts, you can read the documentation