I had the same $%^&*())$# problem,sounded like a bird on meth,comes from the fork shroud,you can give it a twist and will temporarily alleviate,but best fix is to skwert some hi-quality aircraft type spray lube up in there,I did and it fixed it for 2 years now.

2005 Model . Two Fast Eddy stickers , a bell and a clock . She's Lola . She tinkles and keeps time . http://s649.photobucket.com/albums/uu211/britbike05/