small network

[Advent Systems]

Hello All & Happy Holidays,
    I know this can get long and involved and I by no means want you 
guys to do my homework for me, just let me know if I'm on the right 
track.   I have (4) pc's and (1) laptop.  After spending 1-2 hrs. on the 
Internet researching I ran my cable, plugged them in, loaded my firewall 
software,  and clicking my mouse about 12 times at each box and my 
network was up and running, including wireless access for my laptop!   
In trying to get the boxes networked with Linux I',I've spent easily 100 
hours "surfing" (I use different distros and everyone seems to approach 
it and place network files and commands differently) I've purchased (3) 
books ( $100+)  and after months I can now ping each machine!  
Questions: 1.) Do I need or "should" I run the same distro on each box, 
I know it sound stupid but hey!  2.) What do I "need" to share my files 
amongst my boxes w/o unduly exposing them to the Internet, ie. NSF, NIS, 
Samba,Firewall, etc. 3.) Do I need to setup one box as a dedicated 
server and the balance of the boxes as clients?
Again I don't need a step by step here.  I'm willing to put in the time 
It's just that its getting ridiculous and want to make sure I'm going in 
the right direction.  To Illustrate how bad it is I have NO boxes 
running Linux at  all right now  ( my boxes are all duel boot w/win2k) 
because  of my file sharing requirements.

Thanks,
Bob Randal