I've been trying to set up a dhcpd / tftp server that would deliver the
kernel and corefs to a system on a PXE boot.. but I'm having problems,
that I believe are in the dhcpd config, included below.

Here's my setup:
PXE Boot:
MotherBoard: Intel 815i
eth0: 3Com 35905b
PXE ver: 2.0

DHCP Server:
SuSE 7.3
192.168.202.100

TFTP Server:
Red Hat 9.0
192.168.200.57

/ect/dhcpd.conf:
option netbios-name-servers 192.168.200.31;
option time-servers timserv.testnet.mydomain.com;
option domain-name-servers 192.168.200.31;
option domain-name "testnet.mydomain.com";
option broadcast-address 192.168.202.255;
option subnet-mask 255.255.255.0;
option routers 192.168.202.5;
ddns-update-style none;
allow booting;
allow bootp;
subnet 192.168.202.0 netmask 255.255.255.0 {
}
group {
host stg20 {
ddns-updates off;
hardware ethernet 00:01:02:23:31:EB;
next-server 192.168.200.57;
filename "pxelinux.0";
fixed-address 192.168.202.120;
}
}

/etc/xinit.d/tftp
service tftp
{
socket_type = dgram
protocol = udp
wait = yes
user = root
server = /usr/sbin/in.tftpd
server_args = -v -l -s /tftpboot
disable = no
per_source = 11
cps = 100 2
flags = IPv4
}


-----------------------

The target does a pxe boot boot, and receives the correct address, subnet,
and gateway... though it displays the DHCP IP: 192.168.200.57 (which is
the tftp server, not the dhcp server.. but maybe that's what it should
read I don't know)

Then it will time out waiting for a response from the tftp server.

I can do a netstat -a |grep tftp and see the service running
I did a tcpdump: tcpdump port 69 on the tftp server, and receive no traffic

I then changed the dhcpd.conf so the tftp server would be in the same
subnet.. and (this time on a RH8 box).. and still no traffic on port 69.
I did not set up the tftp servcie on this second test box.. I was just
looking for trafic at this point.

Can anyone see anything obviously wrong with my dhcpd.conf, or on what I
have done here to get it to work.

I am trying something similar, but I can't get TFTPD to start. How do I get it running?

Any other advice would be great

I don't understand your sentence

"and receives the correct address, subnet,
and gateway... though it displays the DHCP IP: 192.168.200.57 (which is
the tftp server, not the dhcp server.. but maybe that's what it should
read I don't know)"

As I read your conf file, and if that 00:01:02:23:31:EB mac is that board, it should get the IP 192.168.202.120, not .57.

Then try from another box (or your server itself) if you can actually tftp the file in the first place.

Hope it helps,
mlp

Read:

http://www.tldp.org/HOWTO/Network-boot-HOWTO/index.html