Current versions of Ill have "snap to pixel" mode: http://help.adobe.com/en_US/Illustrator/14.0/WS714a382cdf7d304e7e07d0100196cbc5f-636da.html.

Edit: Here's an example how image looks like in Ill when pixel preview is accordingly on and off:

![pixel preview on][1]![pixel preview off][2]


  [1]: https://i.sstatic.net/1rIZS.jpg
  [2]: https://i.sstatic.net/HAHVk.jpg

In first case when also "Snap to pixels" is on, nodes will be snapped to pixel grid.