A few links for research on your newspaper assignment!
All British Newspapers online (links page)
http://www.wrx.zen.co.uk/britnews.htm
Press Display - Newspaper Front page (in left hand tool bar, 'Titles by Country' click 'UK')
http://www.pressdisplay.com/pressdisplay/viewer.aspx
National Union of Journalists
http://www.nuj.org.uk/
Wikipedia Article - Media Ownership (with good links for further reading!)
http://en.wikipedia.org/wiki/Concentration_of_media_ownership
Campaign for Press & Broadcasting Freedom
http://www.cpbf.org.uk/
British Journalism Review
http://www.bjr.org.uk/
Media Channel
http://mediachannel.org/
Press Complaints Commission
http://www.pcc.org.uk/
Tim Worstall's Newspaper Watch
http://timworstall.com/category/newspaper-watch/
Cyberjournalist
http://www.cyberjournalist.net/
Spin Watch
http://spinwatch.org/
Media Lens
http://www.medialens.org/alerts/index.php
DigitalSpy
http://www.digitalspy.co.uk/
The Guardian Media Section
http://www.guardian.co.uk/media
The Independent Newspaper Media Section
http://www.independent.co.uk/news/media/
FAIR (Fairness & Accuracy in Reporting)
http://www.fair.org/index.php
I Want Media
http://iwantmedia.com/
Spiked (Politics and Media)
http://www.spiked-online.com/
Media Studies Sites
The Media Theory Site
http://www.theory.org.uk/
Media Knowitall
http://www.mediaknowall.com/
Many newspapers have a web presence as well as the printed version. I'm not going to list them all here as I'm sure you all know how to use google. Visit them and have a look - it's worth your while.
Remember: you need to look at 1 national, 1 regional and 1 Sunday (national) newspaper.