While I am planning a family trip to California, I found Gogobot app.
This application lets the user to plan for group in different locations.
Gogobot has a website too, and their new app looks great and friendly user interface.
Once I create a trip, I can invite other people and add a hotel, restaurant or place.
It has three categories which are Stay, Eat and Play.
Pros:
Plan a trip collaboratively with others
Cons:
The new interface within this app is hard to get used to it.
The information about the restaurant and hotel is not really helpful.