E*TRADE Mobile Pro for iPhone, and iPod touch is here! The iPhone's large, touchscreen display really makes a difference compared to the BlackBerry version (since the Storm is strangely not supported). Now all they need is a Power E*TRADE Pro version, assuming the performance of AT&T's 3G network is up to the task of active trading.
P.S. iPhone Software 3.0 Beta users are currently out of luck, as E*TRADE Mobile Pro 1.0 unexpectedly quits upon log on. The Mobile Pro issue should be easy enough to remedy by the time the final version of 3.0 is available to the masses.

