I still don’t go for the idea of managing my personal financial info stored on someone elses servers, i.e. not my bank or other known “trusted” provider, but there are some useful apps in this list. Zillow is mentioned, along with Rentometer. Note that “trusted” is in quotes. 
Top 25 Web 2.0 Apps for Money, Finance, and Investment:
The smart way to money management, personal finance, and investing is to use the right tools ? tools that aren’t so intimidating that you’ll ignore them after a while. This guide to the top 25 web 2.0 applications should help you with the above will come in handy when it comes to managing all your money concerns.
