I am currently putting together a Canine First Aid kit and have found several really usefull sites with suggestions. I am partial to the thrid one on the list below; however none of these sites advise getting a Small Animal Breathing apparatus, which is crucial incase you need to do CPR. This is obtainable by contacting either an Ambualnce service near you or your local Fire Dept. should also be able to help you purchase one for your kit.
The one thing that the last website does advise and I strongly recommend is to place a pair of wire cutters, pliers or even a bolt cutter in the first aid kit.
Why, you may ask??
Very simply, if you come across an animal that has punctured itself on rebar, wire fencing, nails (and there are some extremely long nails out there) you will have a way to deal with the wound at the site, by cutting the protruding item and bandaging the wound to help stop bleeding, rather than risk damaging or injuring the animal further by transporting an open wound with a protruding item, that could get jarred/banged around. Never ever remove a protruding item from a victim, this could cause further hemoraghing of the wound, always cut close to the wound and bandage it up quickly!!!
I have seen this on one occasion

also, the last site advises having 3" x 3" sq guaze on hand and lots of it!!
I would suggest, just by going by my CPR/First Aid courses and a little experience, to have some of varying sizes and a roll of it, in case you come across something out of the ordinary and you then have the gauze to fashion whatever is needed for that particular injury. All fabric stores carry gauze and for relatively little money.
Since Spring/Summer/Fall is coming up shortly

Lori

and the Pugmen!
http://www.canismajor.com/dog/fstaidk.htmlhttp://bullmastiffinfo.tripod.com/firstaid.htmlhttp://www.agilitymb.ca/learn_firstaid_kit.htm