My friend just did this and got a free iphone. All u need to do is sign up to this advertising site and take one of the free offers (i"d suggest the LOVEFILM one cause its totally free) and then use your own personnel url to get ur friends to do the same and they send you the free gift!! : ) Im really close now, just need about 2 more people. heres the link to the site
http://apple.freebiejeebies.co.uk/362971
http://apple.freebiejeebies.co.uk/362971