dhcp connects but cannot resolve names

[oxy <oxyopes@googlemail.com>]

Hi friends,
i get a wifi dhcp connection at home, but cannot resolve names.
I can ping ip addresses around the world, but cannot ping hostnames,
since they are not resolved. I configured with iwconfig, iwpriv
as shown bellow. The first configuration i tried with network manager.
No success, but many people report problems with it anyway.
Take a look at my main steps to connection:

me% iwconfig ath0 essid <server name> key <numbers>
me% iwpriv ath0 authmode 1
me% iwconfig ath0 ap <hardware address>

me% dhclient ath0
There is already a pid file /var/run/dhclient.pid with pid 5104
killed old client process, removed PID file
Internet Systems Consortium DHCP Client V3.0.4
Copyright 2004-2006 Internet Systems Consortium.
All rights reserved.
For info, please visit http://www.isc.org/sw/dhcp/

wifi0: unknown hardware address type 801
wifi0: unknown hardware address type 801
Listening on LPF/ath0/<hardware address>
Sending on   LPF/ath0/<hardware address>
Sending on   Socket/fallback
DHCPREQUEST on ath0 to 255.255.255.255 port 67
DHCPACK from 192.168.2.1
bound to 192.168.2.36 -- renewal in 164964 seconds.

me% echo "but i am connected, look the ping .."
me% ping 64.233.187.99
PING 64.233.187.99 (64.233.187.99) 56(84) bytes of data.
64 bytes from 64.233.187.99: icmp_seq=3 ttl=240 time=194 ms
64 bytes from 64.233.187.99: icmp_seq=4 ttl=240 time=189 ms
64 bytes from 64.233.187.99: icmp_seq=7 ttl=240 time=186 ms
... ... ...

me%  ifconfig ath0
ath0      Link encap:Ethernet  HWaddr <hardware address>
          inet addr:192.168.2.36  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::bla bla bla/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:572 errors:0 dropped:0 overruns:0 frame:0
          TX packets:493 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:186953 (182.5 KiB)  TX bytes:102942 (100.5 KiB)

me% route add default gw 192.168.2.36
me% nslookup www.yahoo.com
;; connection timed out; no servers could be reached

me% echo "its a debian etch, madwifi driver, atheros r5.... card :-) \
    thanks in advance for any help ..."