How can I estimate effort hours in a Project?

I am beginning an indie game with a small team, the team in divided in diferent groups with different functions, I have been reading some agile methods and I would like to use the Kanban method in this project so I don´t know how many time the project will last, should I estimate an effort hour for the project and divided it for weekly effort hours and daily effort hours or should I estimate daily hours for every group in the project and associate very hours with different tasks?

You can give time estimates for the tasks. These will probably be wrong however.

After finishing some amount (say one week) you should go back to the original estimates and find out what took longer and what actually was done quicker than planned.

You should involve your team in this process and absolutely make clear to them that it isn't a personal fault if they needed more time than expected.

Thanks!

I would be tempted to say that a working methodology (such as scrum) would allow you to work, and revisit evaluations as you go...

This is slightly related and I'm sure you can tweak it to fit your needs:

http://www.gamedev.net/page/resources/_/business/production-and-management/estimating-effort-for-small-projects-r3968