Blue genie, Milderina, Icylemon,
I have that whitish (something like white heads) in my nipple. Yes is normal.. What I normally do is to clean my nipple by squeezing and dig out the whitish thingy. My Fren told me, whenever I have time, I must clean the whitish so it will not block the milk flow later when you breastfeed.
So, I normally do that when I having a shower.
I also notice that once I clean the whitish thingy, and when I start to sequeeze more (to make sure is clean), I will get transparent liquid coming out. I guess that is what I called colustrum.