Q: Is there any way to run spreadsheets (Excel) with this iPhone software? Also is there an app that allows me to use Bluetooth stereo headphones?
A: The iPhone provides native support for viewing Excel spreadsheets, although there is no built-in way to simply store them on your iPhone. The viewer is designed to display them from e-mail attachments or links on web pages.
A third-party app available on the App Store, FileMagnet (iTunes Store Link) will allow you to transfer documents to your iPhone via WiFi for storage and display on the iPhone itself. Several formats are supported, including text, PDF, Word, Excel and Powerpoint.
In terms of Bluetooth stereo support (A2DP), there are no applications that provide this capability, nor are there likely to be any in the near future. Bluetooth profiles are based on lower-level drivers that third-party developers do not have access to. If A2DP support is to be added to the iPhone in the future, it will likely have to come from Apple themselves. Presently, the only Bluetooth profiles supported are Handsfree and Headset, intended for use with the phone portion of the iPhone. Note that audio from non-phone-related applications does not play through the Bluetooth headset.