I know Halloween is fun and exciting for the kids...getting dressed up...getting candy and such....but please keep them safe. I have found a few sites that I like on Halloween Safety for Kids and our Pets! 
This Safety Tip is from: http://www.thriftyfun.com/tf929815.tip.html
Regardless of if your costume is bought or homemade, please use a  "homemade" face.  As a volunteer with our local fire dept and a first  responder, I find it sad that every year at least one child is injured  by their costume.   
Instead of a mask, consider using makeup to create the face.  A mask  is often bumped out of place and blocks vision.  Some masks also contain  lead (from the paints) which can be inhaled.  Other times small  children have had them block their nose and mouth while sleeping and  have suffered from a lack of oxygen.  So instead of a mask, draw those  whiskers and such on the face.  
Also, if your child's costume has a tail, have them practice  stairs with it.  You may need to shorten it so that they don't trip over  their tail.  Don't let them ride their bikes with sandals, tails or  other costume parts that can be tangled in the brakes or spokes of the  bike.  
Also avoid materials that are highly flammable.  Try to make it  with pajama fabric if you can. It is marked as being flame retardant.   One step too close to a Jack O lantern can result in third degree burns.  
Try to place some reflective tape on all sides of the costume and  give your child a flash light.  Avoid costumes that are of dark or  black colors.   
Lastly, please don't use draw strings around the face or neck  area.  Use elastic string instead, and make sure it is loose and won't  choke a child if caught on something.
Source: very sad experiences 
 
The following is a list of the safety sites that I found very helpful:
www.safetyathome.com
www.vetmedicine.about.com
www.thriftyfun.com 
www.halloween-safety.com 
 Some of the above sites have lots of other great safety information that we all can use, please check them out.
Have a safe & fun Halloween!