NTP on port 123 is going to be a LOT to work on. If you have needs for VERY high accuracy it's what you use. Commercial NTP time servers are in the $2K range See:
http://www.ntp.org/
SNTP is easier to deal with (this is what your PC uses to sync up)
http://www.micro-examples.com/public...nal-clock.html (the code for this is over 1K lines)
Time Server on port 37 is easier
http://www.codeproject.com/KB/IP/udptime.aspx
DayTime server on port 13 is even simpler

I would start your efforts programming a Time Server client using a PIC ENC28J60. Once you get a little background and practice start working on the server.

As far a I know no big company ever made a 60/77khz NTP server. There is too much phase shift every day. Most people use GPS as a source for an NTP server. However a 77Khz time source would make a good backup.

I expect to work on such a project down the road but I will probably use something with a little more power like an Ethernut http://www.ethernut.de/en/index.html They have an example of a SNTP client that is less than 200 lines but written in C code.

Regards
Tim