It heavily depends on the programs you use (Outlook Express, for example, doesn't like it), but - in general - it's possible to network those 2 PC's and have the files on one accessible on the other.
Or add a third machine (a "file server" to the network) for storage of shared files. That's the standard solution in a business.
Kees
At my place of work there are two computer systems (w/Ter,kybd,m)running Windows XP networked together that share a common printer. There are duplicate files and email addresses/messages on both machines. I want to have everything on one machine while being able to access the information on it via a second dummy terminal, keyboard and mouse that replaces the other system. I would like it so two people could work on both terminals as long as they do not work on the same file. Is this possible and what do I need for equipment? I was told it was not but I seek a second opinion from anyone who may be knowledgeable in this area. Thank you for any assistance you can provide.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic