Millennial Media, one of the largest mobile advertisers in the US, has released their August MobileMix. Based on their ad impressions, they estimate that Android now commands 26% of the Smartphone market - up 7% month-over-month. If accurate, that puts Android 7% ahead of RIM - but still 22% short of iOS.
Other tidbits: smartphone impressions gained 3% in the last month, up to 51%. The original Motorola Droid surprisingly still holds 9.44% of the market as the second most popular phone (obviously, the iPhone is first); based largely on the success of the Droid, Motorola is now the third largest device manufacturer.