Have a look at Bizhelp 24 and the section on Marketing Planning and any other relevant sections for next week.
Also check out : http://www.startups.co.uk/6678842910840924240/marketing-plan.html
Institute of marketing. Look at some of the download articles on the right hand side of this link: http://www.cim.co.uk/resources/plansandstrategy/home.aspx