Detect my own app's version or use existing update notifier when publishing on my website and not the market

Question

I would like to notify the users when there is an update because the updates will be coming from my own website and not the market. However, do not want to have to update two places.

Either that or I would like to share the existing update notifier that is included with android. I am planning on uploading the app to one of our websites instead of the market.

Thanks!