One thing the iPhone is not real good at is battery life when transferring data over a 3G connection.

One thing that the iPhone does really well is seek out public Wi-Fi networks.

Many of us gladly connect to “free” hot spots to save battery life BUT that presents big security risk. The iPhone really doesn’t inform you that you are associating the phone with a true AP or an ad-hoc device. One must use care with sending passwords over an “untrusted” network! While not exactly trivial to do… it isn’t exactly hard for someone to set up a rogue AP. These devices can cause you a lot of aggravation. These ad-hoc APs could be used to perpetrate a Man-in-the-Middle attack while using the hot spot. Additionally, it could be used to “poison” your phone’s browser cache, which in turn could be used to display fake Web pages or even steal data at a later time. It’s always a good idea to clear Safari’s cache after connecting to an unknown AP. So how does one go about clearing the cache on the phone?

Choose Settings > Safari > Clear Cache.