Apps Center is developed to give you one-stop setting menu. If you're developer, you can adapt your apps to this app by easy way(adding a xml file as meta-data) like home widget. This version have been improved for Xperia
Install apps from your SD card with this utility. Users installing non-market apps no longer have to use the G1 browser to find/install an .apk. Apps not compiled on SDK 1.0 (any app released prior to Sept 23rd, 08) won't work, since they don't work on Android period