i managed to collimate mine fairly well using a laser collimator by trial and error (and cursing lol) but i have since found this article:
http://gmpexpress.net/~tomhole/blaser.pdf
it seems the best combination is a sight tube for secondary alignment, followed by a laser for primary alignment.
i think i will buy a sight tube at some stage as i know the alignment is not perfect, but currently i have pinpoint stars so im not stressing too much :-)