In no particular order, SI offers some photographs of landmark moments for (US/Canadian) women's sports (h/t psheehy):

1926 - Gertrude. A no-brainer for SI: She's wearing a swimsuit!

(17 years of nuthin'? How about d'em Red Heads?)

1943 - A League of their Own. As good as the movie.
1947 - Babe. They mention her 1932 Track and Field AAU blitz, but she was also an AAU All-American in basketball in 1932. And '31. And '30.

1957 - Althea. 'nuff said.

(15 years of nuthin'? How about Diane?)

1972 - Richard - Maybe the wrestlers should blame him?
1973 - Billie Jean - Wonder what ever happened to that little piglet
1977 - Janet - She's in the brick. House.
1978 - Aiie! It's a Girl! - And 22-years later it was, Aiie! It's Lisa Olson!

(14 years of nothin'? How about Joanie?)

1992 - Manon - Kick save and a beaut!
1996 - Oh, Atlanta! - But will they be saying, "Dot's all folks?"
1997 - Kym and Lisa - Sigh. I miss the black Liberty road uniforms....
1998 - Cammi - Can't we check now?
1999 - Brandi - Oh, those abs of steel

2001 - ESPN - Imagine missing Marist.
2003 - Annika makes like the Babe
2006 - Effa - Force 10's inspiration?
2006 - Pat - Nothin' rocky about what she tops.
2007 - Wimbledon - Finally even-steven
2008 - Hayley - O, Canada!
2008 - Danica - Yes, mine is bigger than yours.
2008 - Ashley - Didn't get the play Danica got, but there was nothing funny about beating dad.