iPhone: Understanding the call-forwarding icon
Symptoms
iPhone Software 3.0 allows you to see if Call Forwarding is enabled by displaying 
in the status bar:
In rare instances, this icon may not appear after turning your iPhone off and on, even though Call Forwarding is still enabled.
Products Affected
iPhone, iPhone 3G, iPhone 3GS
Resolution
Try turning iPhone off and then on again.
To check if Call Forwarding is enabled, tap Settings > Phone, and then tap the Call Forwarding option.
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