Yes, thats true that if you select DHCP then you can not put static DNS . But for what purpose you want to put static DNS.

Is there any problem you are facing with your Router

No you can do it...I just didn't see the manual DNS section at the bottom of the page...

My plan is to use OpenDNS instead of relying on my ISP's servers. One reason for that is to allow custom control of DNS queries -- I'm thinking about blocking the entire .cn TLD to put a stop to the deluge of Chinese webbug spam on my network and I'm tired of playing whackamole with <randomrubbish>.cn

Just blocking '.cn' as a keyword in the router doesn't work as I can't find a way to tie it to the end of URL position (like \.cn$ --- am I missing something?)

Im trying to figure this out myself I have "version 3" of WRT160N

I'm trying to have the builtin DHCP server in the WRT160N send clients FIRST to the internal (win server 2003) DNS I have (and my ISPs DNS lower down the list). The problem is that from what I can tell, is that the even though I properly list in the webinterface of the Linksys WRT160N router my DNS servers, somehow it adds itself  (192.168.x.1)  as the first DNS server, even though I specifically add my own list of "Static DNS entry number 1, 2 3". This is entered on the Linksys Basic Page towrds the bottom.

Since you have Windows Server 2003, I suggest setting it up as the DHCP server for your network and completely disabling the DHCP server on the WRT160N.

Two reasons: first, as you have found, the WRT160N makes itself the first DNS server in the DHCP data, and it is not optional. The WRT160N has a built-in DNS server for your convenience, which brings up the second reason: the WRT160Nv3's built-in DNS server is bugged and Linksys appears to be in no hurry to fix it. The only workaround is to manually specify DNS servers on the clients and leave 192.168.x.1 out of the list. It's easy to do this in Windows, but not easy in OS X 10.5 and later. See http://forums.linksysbycisco.com/linksys/board/message?board.id=Wireless_Routers&thread.id=146716&view=by_date_ascending&page=1

I have a wmp11 adapter, I believe my driver is messed up. How do I reinstall the friver