“I had forgotten,” a colleague said recently, after an off-the-record meeting with Apple’s (AAPL) CEO, “what an interesting and dedicated student Steve Jobs is of other people’s businesses.”

Take, for example, the advertising business.

If you are in the ad trade, or care about it, or just want to see a first-rate sales pitch, you could find worse ways to spend 15 minutes of your life than to watch the last quarter hour of Apple’s preview of iPhone OS 4.0, the new operating system for the company’s growing family of mobile devices.

That’s how long it took Jobs Thursday to presents iAd, the mobile advertising platform that Apple is bringing to the iPhone and iPod touch this summer (and to the iPad this fall).

The video can be streamed from Apple.com in QuickTime. The iAd portion starts at the 44 minute mark.

“We think most … mobile advertising really sucks,” Jobs begins, before making the case to an audience of reporters, developers and agency reps that Apple can do better. His evidence: three Apple-created sample interactive ads that are a rarity on any screen: advertisements on which you might actually want to click.

The iAd story was front-page news in the trade press Friday morning. Sample headlines:

• Advertising Age: “Apple’s iAd Not Game-Changing, but Will Move Market.”
• paidContent: “Here’s How Apple Will Beat Google at Mobile Advertising”
• New York Observer: “Apple Is Starting to Freak Us Out”

Jobs pitch: Apple will provide the tools, sell and host the ads, give developers 60% of the revenue and by the time the service debuts this summer, offer a billion impressions a day to one of the world’s most valuable demographics.

In a note to clients Friday morning, Piper Jaffray’s Gene Munster found Jobs’ 1-billion-a-day claim, to say the least, “aggressive.” None the less, he left the pitch a believer:

“We believe we are seeing Apple enter a meaningful new category, as it did with the App store,” he wrote. “We believe this type of mobile inventory will likely capture the biggest portion of mobile ad dollars through 2013. Given the iPhone OS platform has 64% mobile browser market share today according to Apple and the mobile web will account for over $700 million in revenue in 2013, we believe that the iAd platform could potentially double revenue in 2013.”

See also:

• Watch Steve Jobs’ iPhone 4.0 keynote
• Apple raises the bar on mobile devices
• Live: iPhone 4.0 preview at Apple headquarters

[Follow Philip Elmer-DeWitt on Twitter @philiped]