A network card plug looks like a regular telephone plug, but it's larger. A CAT5 cable is a regular networking cable you see at WalMart or OfficeMax...they look like larger phone cords.
The plug looks like this:
You may or may not have lights...
A Crossover CAT5 is a special CAT5 cable that has the outer two wires switched so that whenever a computer is attached to it, it creates it's own IP address. All the Crossover cables I have had were always yellow, but I don't know if that is a standard or not.