i dont know whether it works for u or not but i have a little bit hard way.
1.Enter this site and draw sth as following with polygon drawing.

2.Then open your firebug on firefox and write this code to console.
var feat = map.layers[1].features;
var format = new OpenLayers.Format.KML({
maxDepth: 1,
extractStyles: true,
extractAttributes: true,
'internalProjection': map.projection,
'externalProjection': map.projection
});
format.write(feat)
3.Run the entered command and get your kml content file. and dont forget the remove "" quotes from your code...(the head and the final quotes) and save it in a file then name it with .kml extension. I have also added red style to my kml...
<kml xmlns="http://earth.google.com/kml/2.0">
<Folder><name>OpenLayers export</name>
<description>Exported on Tue Jul 10 2012 09:12:36 GMT+0300 (GTB Yaz Saati)</description>
<Placemark><name>OpenLayers.Feature.Vector_148</name>
<description>No description available</description>
<Polygon>
<outerBoundaryIs>
<LinearRing>
<coordinates>11.591796875,48.76708984375 5.8349609375,43.88916015625 10.185546875,36.37451171875 18.0078125,35.89111328125 20.7763671875,39.93408203125 23.720703125,44.98779296875 22.314453125,47.71240234375 22.2265625,47.75634765625 11.591796875,48.76708984375</coordinates>
</LinearRing>
</outerBoundaryIs>
</Polygon>
<Style>
<PolyStyle>
<color>#a00000ff</color>
<outline>0</outline>
</PolyStyle>
</Style>
</Placemark>
</Folder>
</kml>
4.The last thing is that double click your kml file.. That's all.

i hope it helps you...