hello.
at work ze need to host our web site. and it's a grawing project. the thing that is now we are considering to build our own zeb server in the work place.
we have made some progress by installing a LAMP/debian. but we are so confused about the DNS.dommane.
can you please clarify the thing please?

You do not have to host the DNS in order to host a website. You're probably better off by letting your registrar or ISP host the DNS unless this is something you really want to do. If you do want to host DNS then you need to install BIND on your server:

sk:~# apt-cache search bind | grep ^bind
bind9 - Internet Domain Name Server
bind9-doc - Documentation for BIND
bind9-host - Version of 'host' bundled with BIND 9.X
bindgraph - DNS statistics RRDtool frontend for BIND9

Start with these packages and these tutorials:
http://www.debuntu.org/2006/08/05/85-how-to-setting-up-a-dns-zone-with-bind9
http://www.debian.org/doc/manuals/network-administrator/ch-bind.html