I am working on a product that I don't feel is completely ready but I have a set of users that are very interested in using it now as "alpha" testers. I would like to give them the product now for free as "alpha" testers, but I would like to later license the software.

Is this possible? Can anyone point me to any links/books/articles/etc?

Thanks.

EDIT: Due to the lack of my clarity and the reponses to the question I thought I should add this statement.

I haven't decided if I am going to close-source or open-source this project yet. The user base that wants to get their hands on it now has kind of surprised me and I was concerned about what my options are as far as being able to give it to them now as open-source and later change to closed-source, or even vice versa.

Thanks to everyone who has answered and commented. I appreciate it the insights.