Arvest Mobile Banking's availability on iPhone via the Firethorn mobile app 
has been highly publicized on the mobile news sites. The rapid spread of this announcement underscores the desire of iPhone users to do their banking via their phone.
According to a March article in The New York Times, iPhone users access news and information, use search engines, link to TV and video clips and listen to music significantly more than smartphone and Blackberry owners and other mobile phone users.
Here are some links to the recent media coverage of iPhone and Arvest Mobile Banking:
Arkansas Business: Arvest Makes More Mobile Moves
CNET: AT&T and Firethorn Bring Mobile Banking to iPhone Customers
Tulsa World: Arvest Bank on iPhone Program