Installer.app is almost complete and ready for firmware 2.0. It looksvery similar to the App store. If you have updated your iPhone to firmware 2.0 you will notice that there are not that many programs compared to 1.1.4 and below. Apple has made it a lot harder and applications need to be updated with a digital signature to run on a jailbroken iPhone.
You can follow the development progress on RiP Dev’s blog. RiP Dev has taken over installer.app from Nullriver. There are also more images there.