Hi,
Is there a feature to restrict user access to particular albums alone? Say that my brother can access only his albums and I can access only my albums as such. Please help!

Yes, but for top level albums only. See the user guide.

Top level albums? Can't get you. Can you please explain? BTW, you guys have the best response time.

Top level albums are, well, the toplevel albums. You can set specific righs only for those which includes all subalbums.

I would like to suggest to take a look at Zenphoto before asking questions that explain themselves on the backend.