See http://beagleboard.org/Getting+Started#step2 for the updated drivers
Mac users: The HoRNDIS driver from Joshua Wise has been updated to
release 5. I've heard reports on Twitter than this fixes Internet
Connection Sharing issues.
Windows users: The drivers have been signed now by sysco.ch, so
installation should be simpler. This does however mean that a 3rd
party touched the binaries.