Not everyone is upgrading to the iPhone 5 and indeed now that the iPhone 4S is $99 and the iPhone 4 is free, with contract, those devices will be around for a long time. And to make your battery last even longer, there are a lot of iPhone 4 cases that include a built in battery pack.
But when I saw Spyder Digital Research and their PowerShadow i4 Battery Case
, I could immediately see that they brought something different to the table. The traditional 30 pin dock has an advantage that so many battery cases must forego. You can plop an iPhone in a dock or clock radio throughout your house and it just charges.
By positioning the microUSB connector at the bottom of their case, and including a traditional style dock, albeit for microUSB, Spyder Digital Research's PowerShadow i4
offers the best of both worlds and does so under $90. I hope they will offer a version for the iPhone 5 as well.