iPhone App Dev on Windows, Starting Questions

I’m a computer science student who’s comfortable with Java and Web programming (namely HTML/CSS/Javascript/some PHP).

A friend has asked for an iPhone application which will be a menu that leads to different sections of an eBook, some simple multiple choice quizzes (just wrong/right on “check button”, no recording or saving scores), and some video clips.

What is the best way to go about this on professionally on a Windows machine? Should I find a mac to work on and use the official xCode program, or is there a reliable Windows alternative? Price of software shouldn’t be an issue, as he’s willing to invest more than enough money to make this app a reality.

Thank you!
-j33k (haven’t been here in a long time)