That would depend on many factors such as your tax status, the amount of risk you want to take and how long you want to invest for.
The best places I can think of for you to look for advice on the web are the motley fool
http://www.fool.co.uk/
Money saving expert
http://www.moneysavingexpert.com/
If you are a basic rate tax payer you can invest �3000 each tax year in a cash ISA . NAtional Savings do a tax free savings certificate were you can put �15000 away in each issue
http://www.nsandi.com/savingneeds/taxfreeinves tments.jsp
Best savings account at the mo is ICICI bank with 6.41% aer.