This is something very interesting and cool ( Scoble has even written about how Linux fonts dont look as good as Mac or Windows.) Sandeep has written about this issue before. And this blog has carried information about how to turn font-hinting on, installing mac fonts here and here.
Sandeep writes on his Datum blog: “The basic issue is that certain basic patents in font hinting are owned by Apple. Though it has been good to never pursue them against Freetype – the font rendering engine for Linux – it was still a contentious issue.
However, now these patents could be expired – which does not mean Linux has to use these… but it removes roadblocks to leapfrog to advanced techniques based on these fundamental algorithms. This idea is [being] submitted to Ubuntu for legal counsel to enable this to happen.”