or if you wanna be a real stralian, and be really cheap like me, you can use a 600ml coke bottle with a 8" piece of water pipe stuck though a hole in the cap. I got the pipe from witworths marine, it is about 1cm od and fits like a glove in the filler holes, so there is no spillage, even when you put too much in, it just comes back out into the bottle again. And i've found, its easier measuring how much your putting in there compared to an oil pump.
if i was rich i would get an oil pump though.
Sam