The new iPhone 3g had glitches, customers around the globe had complained about dropped calls & connection issues with 3G networks. Such issues were mainly targeted when calls were handed off from a 3g network to slower network.

To resolve this apple confirmed that the new iPhone 2.0.2 update does indeed include changes to address issues related to 3G reception. USA Today cited company spokesperson Jennifer Bowcock as saying, “The software update improves communication with 3G networks.”

So if your iPhone is causing you trouble the best way around update to 2.0.2

Source [ Yahoo, ]