I'm looking into creating a community site for my church. Mostly to have a core place to put data and make it available for different groups of church members (volunteers, ministry areas, etc). One of my requirements is that it hook into other social networking tools (facebook, twitter, etc) for updating our information and for sending notifications. Another requirement is that I want users to be able to log into the site using credentials that they already have. All of our staff have accounts through our Google Apps site, so I would like them to be able to login using those credentials. For parishioners I feel like they are much more likely to remember their Yahoo/Google/Twitter account info than the info for our site.

All of that intro and this is my question, what is the best module for third party authentication? I've ran across RPX and it looks awesome. I installed it on a localhost install of drupal that I had and it worked well aside from the fact that I didn't have an smtp server setup for it to send out notifications. Is this the answer to my requirements? How well does it work with gathering information from these services?

Thanks all.