Understanding Local Networking - help please?

[DB]

Evening All,

I'm going a bit round in circles (again!), this time it's LAN networking 
which is causing my discomfort...

I've got a desktop & a laptop, both running Fed 11 & KDE (both installed 
from the 11-KDE live CD), the LT since just after the release, the DT 
since the weekend.  There is also my wife's XP machine.  All 3 are 
connected by cable to a D-Link 524, which in turn is cable-connected to 
the ISP's Scientific Atlanta router.  All 3 machines connect without 
problem to the outside world, BUT I don't seem to be able to get any joy 
out of trying to swap files between them.

I tried Samba and SMB4K but neither Fedora machine is able to see 
anything in its Network neighbourhood.  (Left the XP machine out of the 
equation for now!)

So then I tried Krfb, but although I set up an invitation on either or 
both machine, I don't (seem to) get any reaction from the other.....

My guess is, I've misunderstood some of the descriptions in the various 
manuals; and/or failed to activate "something" to make signals go up one 
wire & down the other.  As far as I'm aware, I set Selinux on both 
machines to Permissive (to stop the string of failure messages while 
trying to get everything installed & updated), & I don't think I have 
any other sort of firewall running... (Last year while still on XP, the 
same machines with the same Nic cards & same routers were able to 
communicate quite happily, and would still recognise the IP address of 
the DT when I converted it to F9).

Does anyone have any suggestions how to proceed??

As ever, enormous thanks to all for any help!!!

Greetings from Austria

Dave