Cialis, Viagra and Levitra will work on women the same way they work on men.
I actually just read a really well done 12 week study that showed viagra enhanced sex lives including better arousal, lubrication and orgasm in women -> http://abcnews.go.com/GMA/story?id=124569
You will need a prescription in order to buy brand name viagra/cialis but you can legally purchase the generic version as a research chemical liquid from ag-guys.com
PDE5 Inhibitors work to increase blood flow. This is how it helps men get and maintain erections. It would be the same for a woman. Increased blood flow to private areas could only make things better.