Of course not. The purpose of iAds is to provide revenue to developers who want to publish "free" apps, but still get revenue.
If you want free apps with no ads, download free apps that don't have ads. Pretty simple.
Otherwise, you're cheating the developers.
While I don't agree with the "relatavistic morals" of the younger generations, if you do, think of it this way. It may be OK to cheat ATT or Apple, but it's really not cool to cheat small developers trying to make a few bucks off an app.
Now, that said, I'd love to see the ability to ad-block in Mobile Safari. Of course, that will never happen, since Apple is never going to allow plug-ins or add-ons in Mobile Safari. I think it's iffy that they might approve this for a browser app. (Have they?)
I'm thinking there could be some solution involving a proxy server and/or VPN and filtering on your PC or server.
(Yea, I know that's relatavistic morals, LOL. But I see web sites differently than apps. Plus, ads on web sites can be SO DAMN ANNOYING. At least iAds stays put in one place and aren't splashed all over the screen.)