Urbanscoop is hit or miss, I might say, but the first time I used it, we went to a Japanese restaurant it suggested and had a great meal. The next time, Jamba Juice popped up.
My favorite app so far, and I'm sure there must be more like it, is "Save Benjis." You can enter a upc code from any product and it will search the web to find out what it's going for online. Helpful for larger purchases. It can search by manufacturer, model number also. It doesn't scan the barcode, though, you have to enter it manually but still a very helpful, free program.
I also like Shakespeare, which is the complete folio in one tiny (again free) program, even the sonnets. Nothing like trying to win an argument by quoting Shakespeare!