I've been reading a lot of comics on the iPad lately, and while I love my iPad for a lot of reasons, I think reading comics is one of the best reasons to own an iPad. The big, beautiful screen brings comic art to life exquisitely, most apps allow you to zoom in and out of bigger pages at will, and the touch interface makes flipping a page as easy as, well, flipping a page. So I have no problem at all with free comics to download on the iPad, and that's exactly what Operation Ajax is.
It's a historical comic (so no superheroes, for those of you into that, unfortunately), about the CIA's operation to cause a coup d'état in Iran in 1953. The app features full sound and motion as you're reading through the pages, along with lots of background information about the real-life story and even some newsreel videos to check out.
And right now at launch, the app is completely free. Excellent deal, and a great way to get started in comics on the iPad if you haven't yet. After that, I highly recommend the Comixology app for buying digital comics directly, and I've been using the free ComicBookLover for reading my own .CBR digital files. I've been reading plenty of things in iBooks, too, but the iPad really seems made for reading some great comics.