Jailbreak: AdBlock

Blacklist obnoxious ads, just like you do on your PC.

On the iPhone, ad-blocking is less about avoiding marketing than it is saving bandwidth, and speeding up browsing on your 3G—or God forbid, EDGE—connection.

LINK

Free

From the App Developers: AdBlock is an extension for MobileSafari that filters out advertisements when you are surfing the Internet from your iPhone or iPod touch.