I'm not sure what astonishes me more about Vermeer's paintings; his attention to detial or the COLOURS!
Woman reading a Letter
Young Woman standing at a Virginal
Lady Writing a Letter with Her Maid
Girl Reading a Letter at an Open Window
Woman Holding a Balance
Allegory of the Faith
Girl with a Pearl Earring
Young Woman with a Water Jug
The Love Letter
Lady with Her Maidservant Holding a Letter (Sometimes called Mistress and Maid)
A Lady drinking and A Gentleman
The Art of Painting
These little things (damn you, Imageshack!!!) harldy do the paintings any justice; I strongly reccomend that you take a look at the Jan Vermeer gallery over at ARC to look at the paintings in all their super close-up high-res glory; that way you can really appreciate the minute detail which go into them.
Also, If you're a fan of Girl with a Pearl Earring, this page offers a (very, very, VERY) thorough study of the painting and has some good info on the man himself.