When you map the drive, check of the box that says "reconnect at logon".

Its a small business 2k3 server...

You have a very small network... but by any chance are you running active directory?
Meaning, does the user have to log into the domain?

If so, then you could have logon scripts.

If not, then make sure that both computers have the same usernames and passwords.

Meaning:

xp box may have 3 users

mary
joe
sally

set all their passwords

go to the 2k3 box and create those three users

mary
joe
sally

Make the passwords the same as what is on the xpbox.

It is much easier to just have a domain, but it may not make much sense since you have such a small network.

Normally you create a domain when there is 10 or more workstations.

I've been setting them up for 5 or more workstations. Its just easier for me and the users.

As for the printer problem...

Don't reboot the computers... lol

Or, get a print server for it and get a switch and plug all three devices into it with patch cables.Then you can map both computers to the same printer through the print server.

pretty easy.

add new local printer, create new port, tcp/ip port, type in ip address, choose correct printer and driver, done.

Now the xp box can print when the 2k3 server is not turned on.

Again, the domain would take care of that too... but you have to leave the 2k3 box on at all times.