what you need is a crossover cable. regular cat5 cables dont transmit information two 2 computers, but to another location that does the switching ( a hub or switch - router ).
you can modify the cat5 cable you have using just a pair of scissors, but that takes a lot of caution, as so you dont cut every wire off, and have to start all over again :tard , so maybe, if you dont trust yourself enough with just scissors, use a pair of wirecutters.
check in the computer and technology section, if this isnt moved there already, for an article on this crossover cable creation. there is a link on how to do it. know this, though, i think that article is the more "professional" way to do it, complete with crimpers, and jacks and stuff, so, if you need any help, pm me or make a post in the c&t section.
good luck. :cool