On occasion, I do use Cisco switches as a DHCP server on the network. There are a few reasons why you might do this. I take the view that if the Microsoft DHCP server dies, you still have the network. You just have to rebuild a DHCP server somewhere. However, if your core switch dies and it does DHCP also, its not like DHCP is your primary concern at that point. If you don't have a core, you don't have anything really. Here is a configuration example I used at a customer site, along with notes to tell what it does.
ip dhcp excluded-address 192.168.150.1 192.168.150.10 <--- This address range gets excluded from being handed out.
ip dhcp pool Data <--- This pool's name is "Data".
network 192.168.150.0 255.255.255.0 <--- This is the network that DHCP will hand out for.
default-router 192.168.150.250 <--- This is the default gateway for the devices getting an IP address from this scope.
dns-server 192.168.150.5 <--- DNS server.
netbios-name-server 192.168.150.5 <--- WINS server.
option 150 ip 72.1.64.130 <--- Option 150 is for Cisco phones. You dont need this for data networks.
