i am googling for last 2 hours but can not find any proper documentation about creating extension for magento go. can any one let me know how can i develop, submit and install an extension on magento go?
As far as I know it is not possible at this moment to apply for a Magento Go extension.
The development for this extension is the same as any other Magento platform extension. In the past there was a form available to request a review and mark is as a Trusted Extension.
During Imagine last year there was a session about it and they where having problems with the distribution of the extensions for deployment, thats why there are only a few Trusted Extensions at this moment.