Because Apple hasn’t even launched the iPad tablet yet and most publishers and marketing firms still don’t have completed apps, which Apple must first approve, there are many unanswered questions about how it works for readers and advertisers alike.

But because so few marquee spots are available, advertisers are jostling for their place on the iPad, which launches April 3. Time magazine has signed up Fidelity Investments, Unilever, Toyota Motor and three other leading companies, The Wall Street Journal reports. Each Time contract is worth $200,000 apiece. By comparison, The Wall Street Journal has signed up six advertisers, including Coca-Cola and Federal Express, for a four-month advertising package for $400,000.

Advertisers are reportedly drawn to the interactivity, video, flash, social networking, navigation, touch technology, downloads and even games that can be embedded on the iPad. Conde Nast's Wired magazine, for instance, is offering different levels of this type of functionality to advertisers. For video, the magazine is asking advertisers to commit to eight ads in a single issue. The Journal did not indicate the pricing structure.

“Some of the things you can do are just mind blowing,” said Steve Pacheco, director of advertising for FedEx. “You are taking something that used to be flat on a page and making it interactive and have it jump off the page.”