We need a little more information to help you, but we have an iPhone Support page that may be a good start in solving your issue.
Some additional information that would help forum members to assist would be:
- Are you connecting via 3G or a tethered solution with your iPhone?
- When your iPhone takes over your SlingPlayer, does your laptop internet connection remain intact?
- Have you tried to un-install/re-install the iPhone SlingPlayer application?
Sling Moderation Team