File size

I am new to WP from Joomla & Moodle so I have a few basic questions that I could not find in the FAQ. Thanks in advance for the answers.

I am using WPMU and BuddyPress.

1. First, how can I increase the file upload size from 2MB in WP and in Buddypress if there is a limit, have not gotten to Buddy yet.

2. I know how to add pdf files to WP, is there a way to have the pdf files open in the actual WP Window instead of a new Window?

3. We plan to use WPMU for online learning, can you suggest an Event Plugin or Calendar plugin that we can use for listing class times and schedules. It would be nice if these could integrate with Google Calender or Outlook.

4. Is there a way to have students collaboratively work on a document in WP using Google documents or some plugin.

Thanks again.