Here are a list of useful sites for 250. 

General

The Observer: Top 50 Blogs

Cook and Hopkins Social Media Report

WikiWorld Theory

Ofcom April 2008 report into Social Networks: Full and Executive summary

BBC and Blogs: Is Auntie Finally Listening? (academic paper on blogging: PDF)

Journalism Blogs

• Andy Dickinson.net
• Mindy McAdams, teaching online journalism
• Neil McIntosh
• Paul Bradshaw: Online Journalism blog
• Martin Stabe
• Screaming Headlines Pete Wilby (good on PR, too)
• New Media Bytes

Journalism Wikis

• Two journalism wikis

PR Wikis

• The New PR Wiki
• PR Books

Student Wikis 

• FliSolo.com

• The Student Room Wiki: Sunderland page

PR Blogs

• EuroBlog2008
• Mediations
• PR studies
• Neville Hobson
• Heather Yaxley

PR Resources

• The Measurement Standard

PR Papers

• Examining the Increasing Impact of Social Media on the Public Relations Practice, by DK Wright and M Hinson for the Institute of Public Relations