There are nics in each machine. There is a hub (I don't know if this qualifies as a switch?) All 3 are cat5 cabled to the hub.
Not one machine can see the others.
The Linux is their e-mail server; the XP holds the business software (insurance stuff; spreadsheet; word processor; presentation). The 98 belongs to the office manager, who's not letting go of her machine.
I'm fairly handy and literate around computers, but networking hardware gets me. It seems to me that we can get these 3 talking to each other.
What do you mean, they cant see each other? Cant ping the others? If so, then make sure u installed tcp/ip correctly on windows machines (on linux, most of the cases it should work with default install), assigned ip adresses to machines and put them in the same network. If they can ping each other, then you are finished, ready to install the aplications (or set up windows sharing/smb).