Here is a copy of the top portion of my /etc/dhcpd.conf file. Using this configuration you should be able to setup any TFTP bootable device to look to your TFTP server for configuration files. For example Cisco 79xx series phones, or SPA5xx series phones.
option tftp150 code 150 = string;
option tftp66 code 66 = string;
option tftp150 code 150 = string;
option tftp66 code 66 = string;
DHCPARGS=eth1;
subnet 192.168.1.0 netmask 255.255.255.0
{
option routers 192.168.1.1;
option subnet-mask 255.255.255.0;
option domain-name-servers 192.168.1.1,;
option tftp150 “192.168.1.1”;
option tftp66 “192.168.1.1”;
range 192.168.1.10 192.168.1.150;
}