If Silicon Alley Insider is correct that Apple’s iPhone 4 is an iPad
, advertisers haven’t taken notice yet. According to a new study from Millennial
, ad requests on the iPad are up 160% in the last month.

With Apple’s iAd platform launching this summer (and the company’s competitor-blocking ad policy), Steve Jobs’ prediction that Apple will serve half of the mobile ads sent in the second half of 2010 might not be that far off. 

Interestingly, Millenial Media found that Apple’s overall ad requests decreased 33% from April to May. And since January, the number of requests has decreased 32%.

But with the company’s iAd platform launching July 1, those numbers are likely to shift. The company is working hard to protect its share of mobile advertising. Earlier this month, Apple unveiled new terms of service that would prohibit competitors like Google from
delivering ads on its mobile products.

And while initial iPad advertisements were discounted as brands trying out a new platform, the huge increase from April to May could be evidence that they like the response they’re getting. It will take a few more months to see if the trend continues, but so far, iPad owners are the kind of highly selective group that advertisers love to target. If ad buys continue to grow on the device, it could be a real winner for the company.

And Jobs’ estimation that Apple will serve 48% of all mobile ads in the second half of 2010 is boistered by some of Millenial Media’s other findings. For starters, the company found that most developers (90%) created apps for a single
platform last month.

And Apple is winning the majority of that attention. According to the study, 56% of developers focused exclusively on
Apple products in May, compared to 29% who worked on Android only apps.

Apple’s new T&Cs are designed to keep other ad networks off its precious mobile products. And if regulators don’t step in, it seems like they will be pretty effective at helping Apple establish dominance in the mobile ad space (and wrestle it away from Google’s newly acquired AdMob). 

Apple products have a 48% share of Smartphone impressions according to Millennial Media. If Apple can keep other ad networks from serving ads in its apps, Jobs’ predictions for Apple’s prospects may not be far off.