Here is a little tip for subtly improved font rendering. Go to a terminal window (Applications-Accessories-Terminal) and type sudo dpkg-reconfigure fontconfig-config.
From the options select Autohinter, Always, and No. If you look carefully the curves of letters should now be just a fraction smoother.
nope, don’t do that! go to System-Preferences-Appearance and click the fonts tab, then select subpixes smoothing from the Fonts tab. Same thing as above really, but no need to go to the command line for it.

After I do this I get the message -
Ignoring nonregistered document `fontconfig-user’
Is that ok, or have I done something wrong.
By the way, I think this is a great site for newbies to linux with the webbook !
it was pointed out to me earlier today that you can also turn this on by going to System-Preferences-Appearance and on the Fonts tab select subpixel rendering, or press the details button to tweak the settings further.
I followed the instructions for the terminal an wondered why I got no change. Then I remembered I had already enabled it in the appearance tab. How embarrassing!