My daughter gets blue feet sometimes. Her doc said not to worry and that it's pretty normal. This is what WebMD has posted...
If you are concerned about a blue tinge to your baby's skin, check his entire body. An off-and-on blue cast to the hands and feet, with pink skin elsewhere, is not a sign of a problem, but rather just a little bit of immaturity to the circulatory system, which will go away over time.
When to Worry:
If there is a bluish cast over the entire body, the blood may be lacking sufficient oxygen. This is very worrisome and you should seek medical attention immediately.
But you don't need to worry if your baby's hands and feet turn blue for a short period of time when the rest of the body is pink. This is merely your baby's immature circulatory system at work.
...I hope that helps.