Something else -- he should offer lots of "fun stuff" for bikes, some "girly" stuff, some macho (since as girls we get to like both, ya know -- either buff our bikes up to be all tough and gritty, or doll them up). Because (excuse the generalization) we do love to accessorize!

Try and find a female employee or customer who is willing to help start a women's biking club. I've seen the websites for the Velo Girls and the Pedal Queens and I'm jealous!

Create a really cool women's section (whether it's for clothes only, or includes other stuff -- even if it's small, it could still be displayed in an attractive/funky way) and then advertize it out front in a bold, attractive way: "Come in and check out our new women's cycling products!" (Or whatever it would say. In other words, have the signage reflect that he has women-specific products.) He may pull some people in out of curiosity, and may pull in some women who had been curious but thought maybe only guys shopped there.

In other words, don't just have women's stuff, but make it clear he values women customers enough to create a space for them, and to invite them in.