It appears Attansic was recently bought by Atheros. However, getting it to work on GNU/Debian Lenny is as simple as:
apt-get install atl2-modules-2.6-686
modprobe atl2
And here it is:
root@gw # ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:1e:8c:18:88:a6
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Memory:dffc0000-e0000000