iPhone StaticI use to have this problem with my original Treo 650. When I got my Treo 700, the problem went away.

For some reason, the iPhone causes interference with my external speakers. Now, I am not even connecting the iPhone to the speakers. The interference is random sometimes and is also triggered by when I get a phone call or text message or when I sync with my Mac.

I am far from the only one who is experiencing this interference. There is a large thread at Mac Rumors on this topic. Also, MacWorld covered the issue.

The image at the top right is an setting you can configure when you hook up your iPhone to speakers. Note, I do not get this option, because I am not hooking up my speakers to the iPhone. It just causes crackling and popping noises that come out of my speakers. Turning off the speakers don't help. I can turn on the airplane mode feature, but then I won't get calls, text messages, emails and web.

One person said, you will just get used to it...

blackberries do this all the time. After a while you just get used to the sound

I try to put my phone a good distance from my speakers, which helps a lot.