Going from big to small, you shouldn't have pixelation problems. It's going from small to big that gives you the blurry, square edges or "pixelation."
Hopefully, you have Photoshop.
http://web.ics.purdue.edu/~phoque/chief/tu...al/tutorial.pdf
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I put this together. Just make sure that step 1 is true, you must have a file that starts off bigger than a couple of inches and is at 72 ppi or more, then just follow along for 7 steps to propaganda bliss!
gl hf
Chief