This year's Medical Research Council - Max Perutz Awards might appeal to student members of the ABSW who qualify. You are eligible if you are "an MRC PhD student with an interest in communicating your science to a wider audience".
The Max Perutz science writing prize is a prestigious award aimed at encouraging and recognising outstanding communication amongst young MRC researchers.Feel free to pass this on to anyone else who might be interested. The closing date for receipt of entries at the MRC is 2 May 2008.
The rest of us might also like to check out The secrets of good science writing. They come from last year's judges.