A MediaCurves focus group of 312 women shows that, while John McCain's 'lipstick' ad did somewhat increase perceptions that Barack Obama has a gender bias, it has not moved very many votes and rates as a below-average ad overall.
Before viewing the commercial, the focus group leaned 43/42 for McCain, versus 45/42 afterward. The changes are not statistically significant given the roughly 6 percent margin of error in the sample (data).
(And, yes, I'm buying time here until the polling update. My laptop broke -- anyone got a Best Buy gift card? -- and it's going to take a bit of time to update the version of the model I have on my backup computer).
EDIT: As one of the commentors notes, perhaps this will move votes if Obama commits another 'gaffe' of a similar variety. I think that's probably true.
Also, note that this study was of women only. We don't know how men reacted.