There is just tons of information on this topic. Start with reading the latest works of Ralph Kimball and Bill Inmon. These are the two leading practitioners within the data warehouse sphere. You can look to the [Kimball Group] to see what they have available. Bill Inmon also has a web site with [lots of references] to his material. There are tons of different online resources, books and tutorials. Most training facilities have a warehouse program. As to interview preparation, you're not there. Memorizing questions and answers is no way to learn a topic. You need to develop knowledge of it and be able to transmit that knowledge during an interview. Anything else is setting yourself up for failure and possibly putting the businesses that you're trying to get a job from at risk. Don't do that. :
Grant has made some good suggestions for the theoretical side of things. For the practical, assuming the SQL Server environment, then there are the MS certifications and associated study materials. There's also any amount of material out there to anyone capable of using Google. As for what you're suggesting with the interview... Assuming you're the one looking for a new data warehouse guy, then ask your existing data warehouse / BI guys for their input into the interview. I would actually get them to lead a part of the interview, with you just watching and making notes. If, on the other hand, you're the one looking for the new job, then I, as an erstwhile employer / manager, would have been very upset to find out that a new team member had misrepresented themselves in interview - indeed, I would probably be looking to get rid of that person from the team as soon as possible. Not a good way to start what you would hope to be a long-term relationship, by basing it on a lie.