So you have 3 questions ..
Answer 1 : Get a crossover cable , connect both the terminal ie. Linux & windowsXp then assign proper IP addresses to both (if you want to use DHCP then decide which one is going to be server.. LinuxBox or Windows Box?).
If you want your LinuxBox as DHCP server then set your WindowsXP box as client ie. get IP information through DHCP.
2. Assign fix IP to LinuxBox, now a days you can simply do that via graphical interface for network.
See this -->
Configuring DHCP server in Linux.
3. Configuring Samba is pretty simple.. install samba rpm etc. and it will creat smb.conf in /etc/samba/ (Most of the time). There edit that config file and its pretty self explanatory. Now it should appear in windows as a LinuxBox and vice-versa.