Someone else mentioned Marion Zimmer Bradley, but neglected to mention the Avalon series. this is strictly fantasy, but nonetheless tells the tale of Arthur from the perspective of the inhabitants of Avalon, all female. The friendships depicted there are diverse, enduring, and quite moving.

Still, it's the only really good example I can think of, and I can't think of any in popular sci fi. Interestingly enough, though, there are some amateur authors who write sci fi on this erotica web site Chuck and I subscribe to, that describe some of the most wonderful female friendships. And I'm not just talking about sexual relationships, either. Most of it's trash, but a couple of the authors are really quite good.