By doing a Google image search and choosing the ones with the largest image size I came up with several very nice online reproductions.
Here are a few links:
http://arthistory.westvalley.edu/ima...RL_EARRING.JPG
http://gallery.euroweb.hu/art/v/vermeer/03b/22pearl.jpg
http://www.oir.ucf.edu/wm/paint/auth/vermeer/
For information on suggested colors, and plenty of other details about emulating Vermeer's technique, try this website:
http://howtopaintavermeer.fws1.com/