Is there a plugin that allows me to create a database?

I want to create a database to hold information, then display that information using a wordpress plugin (which could have buttons to sort the tables in various ways).

On a side note, is it possible to tap into the table that holds all the user data? Because basically I just want to keep a table that has all of the registration information, plus additional information such as phone numbers, titles, etc…

Thanks for any help ??