Does a gmail account sync through IMAP or POP?
Originally Posted by Corey
Yes, it syncs through both.
What email providers work best on the iPhone?
I have gmail, comcast, and my schools email through IMAP & they all work great.
Which email providers create the most problems?
Not that I know of.
Is there a dedicated Google Voice app yet?
Yes there is a dedicated Google Voice app free in the App Store.
How difficult is it to create a ringtone on a PC?
Audacity is a free ringtone making program for the PC but there are numerous ringtone making apps in the App Store as well. The downside is you have to import them through iTunes using either method.
Is there a way to create custom notification sounds without jailbreaking?
There is not in iOS4 but in iOS5 they have addressed this feature so you WILL be able to.
What's the battery life for moderate use?
Battery life easily gets you through an entire day. What I used to hate with my Evo4G was the battery would continue to drain without me even using it. The iP4 has much better battery management.