Why is that when you wake up you put on a Tallit Katan and then you go to shul and put on a Tallit Gadol? How is it that you can say two different brachot? If it is in fact, that each peice of clothing gets the the chance for a new bracha, are there any other mitzvot, aside from food, where we recite a bracha each and every time we do the SAME action? Of those allowed are there any we commonly do multiple time as we do with the Tallit?
The custom among (as far as I know all) Ashk'nazim (and maybe among others also?) is that someone who dons a talis katan in the morning intending to don a talis gadol later (for prayers) does not say a b'racha on the former. However, I have no citation for this: I'm not seeing it in the Mishna B'rura, and certain parts of Shulchan Aruch Orach Chayim 8 seem to directly contradict it (cf. Double AA's answer).
Update: As Shalom mentions in a comment on this answer, MB 8:24 cites with approval the practice I am familiar with.