A common complaint among iPhone owners is the lack of expandability. iLounge reports that the problem will be solved in April, thanks to the ZoomIt SD card reader that plugs into the iPhone's dock connector.

ZoomIt's site says, “Get ready...our product will be announced Tuesday, February 9” but they're already taking orders—and offering a $10 discount off the $59.95 retail price—for those who order now. Shipments are scheduled to begin in April, and “the first 250 buyers will receive a free 4GB SDHC card from Kensington Technology.”

They don't provide any details on the device yet, but from their pictures it appears to be about 1.25” x 2”. The add-on lets you access files on an SD card using the free zoomIt app in the iTunes store. The app has a file manager that lets you transfer files back and forth between the SD card and your iPhone, but it isn't clear how much you'll be able to access data on an SD card directly from iPhone apps. All they're saying so far is that you can “display/view a file with a format supported by the SDK 3.0.” But they do say you can take a picture and store it directly to the SD card, and there's an interface to iPhone email to let you attach files or photos to messages. ILounge says it includes support for file types including MS Office apps and PDF. Future plans include support for streaming music and videos (meeting Apple's DRM licensing checks) from SD.

It will be interesting to see how much effect the reader has on battery life.. The fact that their app includes a battery status indicator would seem to be a hint that the hit is noticeable. But for those who have been waiting for the ability to take more tunes on the road, it will probably be well worth it.