You can buy a Canon 500D closeup filter in 77mm, I have one, never really used it too much, I have the Nikon 60mm micro, 105mm micro and the 105mm VR micro.
It's a great closeup filter to use on your telephoto, to give you Macro lens with a fairly long shooting distance, I tried it on my 70-200 VR.
http://www.the-digital-picture.com/R...ns-Review.aspx
http://xoomer.virgilio.it/ripolini/whatsnew_2.html