Vodafone Mobile Number Portability in India |Mobile Number Portability: Idea, Vodafone

You can join Vodafone in two simple ways:

Walk in to the nearest Vodafone Store or Mini Store
Just carry the following documents to any Vodafone Store:
-Vodafone Mobile Number Portability form (available at any Vodafone Store)
-Vodafone Customer Agreement form (available at any Vodafone Store)
-Self-attested photograph of yourself
-An address proof with your signature

More details here http://www.vodafone.in/mnp/pages/what_is_mnp.aspx