If you're looking for a best practice on developing mobile strategies, take a look at what E*TRADE is doing. They had a successful launch of an application for Blackberry devices last summer. They are following that today with the release of an application for the iPhone and iPod Touch. See their press release. They have some good numbers on how well their mobile service has done to date. Forrester Research will be publishing a more in-depth analysis later this month. Stay tuned.