you may try the sight-reading series published by Faber called
Improve your Sight-Reading. I use it together with that publishhed by ABRSM for my G8 exam.
2007-04-09 16:17:46 補充:
the series contains books suitable for students of G1 -G8also the point I would like to emphasise is that practising sight-reading is not only for exam purpose. it should be done regularly.)