How can I go full-time on my startup with H1B visa?
prpon: Based on your description, you seem to be on EAD or will qualify for one (Employment Authorization Document).A person in the final stages of green card qualifies for AC21 (American Competitiveness in the Twenty-First Century Act of 2000)Being on an EAD allows self employment provided that 
a) It is a full time employment 
b) Your new responsibilities are similar to the one original green card application.For more information refer to the AC21 document or one of the several online forums.
Here's one I recommend:
http://imminfo.com/Library/AC21_issues/AC21-portability-self...