I don't think I ever did networking with DOS. Windows for Workgroups, with some kind of packet-driver and Trumpet Winsock, might work. It has been ages since I tried that, so I don't remember much.

If your DOS PC has a serial port, it might be easier to add a similar serial port (maybe on USB?) to your XP machine, and use X/Y/Z-modem over serial to transfer the files.

you need to load some sort of driver in dos. maybe look on the 3com site for it

Ask Google for Network bootdisk.

Not only do you need the NIC driver you would also need some sort or tcp/ip stack since DOS 6 doesn't have one built in. I think the later versions of DR Dos and IBM PC Dos did have built in networking though, or of course WFW 3.11 would also work.

TCP/IP was also possible with MS stuff, but don't ask me how... I've built a Multi-Networking bootdisk at the time, it supported different NIC's and IPX/SPX or TCP/IP. I didn't need a specialized TCP/IP stack. Sadly, i can't remember much more...

Subjunctive, you should look for a ready-made bootdisk, like h-a-l-9000 wrote, and adapt it to your NIC and system. The 3COM NIC should be supported, you'll need a "DOS packet driver" for it.

How about installing Windows and dual booting? Pehaps even just Win 3.11 for Workgroups?

it would be slow but a null modem cable would work no problems

Thanks for the suggestions. I was able to find a few different network boot disks through Google. "Bart's Network Boot Disk" in particular looked promising:

http://www.nu2.nu/bootdisk/network/

Will try it out and see what happens...