Asus does supply some Linux drivers, but they are specific to RedHat and SuSE 
- I couldn't get them to compile for Mandrake 9.2.  I have an A7N8X-X, with 
an NVIDIA/Realtec 8201BP PHY ethernet controller that uses a special version 
of the 3com 3c905 driver that won't compile properly.  I've dissabled it, and 
the on-board sound, in favor of supported cards.

Check the Linux hardware database and check the vendor websites for drivers.