Senator Lillian DeHaven (Anne Bancroft) heads up a committee trying to get women into the Navy SEALS. Through some political wheeling and dealing she gets the Navy to agree to a test subject. The one picked for the test is Lt. Jordan O'Neil (Demi Moore). Soon O'Neil is shipped off for SEAL training and is not exactly recieved with open arms. Master Chief John Urgayle (Viggo Mortensen) tries everything to get O'Neil to quit. Eventually some of her male counterparts start to except O'Neil. She becomes one of the guys so much that during a brawl with Urgayle she tells him to "Suck my dick!" The military old guard expected O'Neil to washout and soon become worried at her success and the fact she is starting to get some press. They begin to take steps to have O'Neil removed from her training.
G.I. Jane is decent but there are countless better movies dealing with the military and war. The majority of the movie deals with the hell that is SEAL training and it starts to get a little boring. Moore gives a good performance and is believable as being worthy of SEAL training. There is not much doubt how this movie will turn out, the ending is quite clear from the onset. If you really want to know what Navy SEAL life is like I would suggest reading Richard Marcinko's book Rogue Warrior. The novelty of a woman in SEAL training wears off quickly and what's left is an average military/combat movie.