I just found out that Tripadvisor provides city guides that work offline. I haven't tried it out in a new city but it sounds pretty solid. They can be found on the app store by searching for "city guides trip advisor" plus the city you are looking for.
It's also nice that it installs to the SD card by default, saving space (although it is still 6mb).
Make sure you run the app first, because on first run it goes and downloads a bunch of data (may take awhile). One bunch is photos which is probably pretty useful - being able to view user contributed photos of the entries without a data plan.
