Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Try leaving it for a while, occasionally it sorts itself out. How's your 3G reception? It could be waiting for a better signal.
I had this problem. Just go to settings->applications->manage applications->google mail-> clear data
Don't ask me why, but straight away all the downloads I had queued started straight away.