I have been using them for 2 months now. They say i9000 as well. So, as cheap as they are, I say go for it. However. I always charge them in the provided charger instead of the phone. Just in case they blow up or something.
i ordered the samsung branded batteries for the i9000
but ordered a generic wall charger
i can't wait to get them because my phone nearly died on me today after a full day's use
it'll be nice to have a spare battery in the car and one at home at all times