It isn't so much the technology behind Zumobi's free app Ziibii that refreshes RSS on the iPhone and iPod touch as it is its presentation. Ziibii, which means 'river' in Algonquin*, extends the metaphor to depict posts from your various RSS feeds as rafts floating along a stream of information.
Watching posts float by is fun concept--for a few minutes at least--and one that's heightened by the fact that stories, photos, and friends' status updates appear in random order as a round-up of all your RSS subscriptions.
Ziibii's feed flexibility is good, but not great. Twitter, Facebook, Flickr, and YouTube are represented, and you'll also be able to add presets from Ziibii's list of popular sites or add your own favorites. Hopefully soon, Ziibii will make it easy to select more popular sources and aggregators, as does Viigo's thorough RSS reader for other platforms.
Of course, not everyone appreciates this 'blended' view, nor the unconventional current-cum-display. My Type-A fellows can escape to a listed view of feeds and flick in either direction to see more mish-mashed headlines. When you're ready to read up on one feed at a time, the Filter button temporarily hides stories from all but your selected source.
Ziibii earns brownie points for including an in-app browser when you want to read a full article, and for being able to post stories to Twitter or e-mail them to a contact.
With the exception of a small library of feeds, Ziibii is an excellent and creative alternative to your iPhone's RSS reader.
*Fun fact: The 'ssippi' in 'Mississippi' is derived from 'zibi.' The etymology according to Wikipedia: "(cf. Illinois mihsisiipiiwi and Ojibwe misiziibi, "great river," referring to the Mississippi River.)"