Not much has changed in the US mobile market over the past few months: Android is still the leader — accounting for 40 percent of the total smartphone market — and consumers’ desire for the Google OS doesn’t appear to be slowing down, reports research firm Nielsen.

The company’s report, based on July 2011 consumer data, shows that Android rose 1 point from its lead share of 39 percent months ago. Apple’s iOS, meanwhile, remained flat with a 28 percent share. BlackBerry’s share fell by 1 point to 19 percent, an impressive feat considering that RIM didn’t have any significant new releases during the period.

Among consumers looking to get a new smartphone within the next year, one-third say they want an iPhone and one-third say they’re aiming for Android. Android holds a bigger lead among early adopters and “innovators” (see chart below).

Nielsen notes that late adopters are the most unsure about which smartphone platform they want. “In politics as in smartphones, these “undecideds” will be the ones device makers will be hoping to win over,” Nielsen director of telecom research Don Kellogg writes.

A big chunk of those undecided consumers are likely looking to get a smartphone for the first time. As the chart above shows, 60 percent of the US mobile market is still made up of feature phones. We’ve noted previously that smartphone makers who anticipate the needs of these less tech-savvy consumers could win big.