I like that cruisedeckplans.com though it did not have all the info on the line that I looked up, but it was very good.
My advise, take a look at the deck plan and determine what the WORST inside cabin is. Would that be awful if you were in that? If not, have your travel agent book a Guarantee (GTY). IT will guarantee you that you will get that category or better. Then have your Travel agent call up their RSM (Regional Sales Manager) for the line, and ask if remarks can be put in the record for a DAP upgrade (Do All POssible). Worst case scenario, you don't get upgraded and you end up in the Inside Category that you may not have picked. Cruise lines always overbook the lead price inside cabins so your chances may be very good for being upgraded. I am speaking from experience.
As has been mentioned here
www.cruisecritic.com is a great site.
Cheers