We made the same feeders last year, and it was these that Kiddo wanted to make again. Last year he was 'into' Special Agent Oso (I think it is a Disney Channel cartoon - he used to watch it at my mum's as we don't have the channel) and in one particular episode, the characters made bird feeders, which is the one we copied.
These could not be any easier or more fun to make :
Smooth peanut butter
Collect some pine cones, preferably ones which are open, and have longer stems still attached.
Tie a piece of string around the stem, leaving a length of tail to attach the feeder to a branch later on.
Spread peanut butter all over the pine cone
Roll the buttered cone in bird seed
Ready to hang in the garden in the trees. We hung ours on the branches that poke though and over the top of the fence. Unfortunately couldn't get a decent photo, but try and get one and post it up (before the feed is snaffled, of course)
Easy peasy and great fun - for us and the birds.