I don't know about RH7.3 but I have done it flawlessly with RH8.0. It can be downloaded
here for free.
Partiton your hard drive for XP leaving unpartioned space(whatever you want to have for RH).
e.g. 40 gig drive - run fdisk and create a 30 gig partion leaving remaining space (10 gig) free. Install XP on the 30 gig space (normal install). Then put in RH disk 1 and reboot. Follow directions and when it asks to partition select " use free space" or something to that nature. RH will be installed on the remaining 10 gig free space and auto-partioned.
** inportant. During the install you come across the section where you choose boot(Grub) and it shows other volumes(XP). You need to name the volume (windows XP) for grub. Once install is finished machine will boot to grub loader asking which OS you want.
1) XP
2) Red Hat 8
Don't forget to name the existing volume(program sees the volume but doesn't give it a name- just type in a name)...I read that makes the difference. I have had windows dual boot with win2000 and then installed redhat 8 - no problems.
e.g. (triple boot)
It will first ask the above menu, then if winxp is choosen, the windows default dual boot menu appears
1) xp
2) WIN 2000
Had to go through 2 menus upon start-up but it was configured automatically and I actually prefered it.
Else you can use partiton magic or system commander.......these programs become your boot loader...they launch the OS. Be sure to make a rescue disk if using these.
Good luck.....let me know if you need more specifics and I will do the install over on my end and give u the exact rundown.
Hope this helps.