IPXE or GPXE is a way to boot not only to a normal pxe but a whole list of other ways.
I generally just make a floppy,cd,or usb to boot the system and it. Should boot just like a pxe boot but from the local media you made.
One of the best places for examples is the gpxe site. If you want to allow pxe to send the ipxe I think the example is there. You'd only do that if you wanted to then boot to ftp or iscsi or such.
Lemme know what you want to do or try exactly for more help.
I think this is what you are trying to do maybe.??
http://etherboot.org/wiki/pxechaining