I just use a knife. Any sharp knife will do. For field dressing, the shorter, the better. Well not too short. I just mean to say, don't use a fillet knife. There really is no need for a saw of large knife to cut any bone while you are field dressing. Many people do it differently. I myself do not cut the pelis. I find that it reveals the meat to dirt.

Here is a good web site that shows how to do it:
http://www.angelfire.com/bc/canuck2/gutting.html

Here's how I do it.
1: Carve out the anus. You might want to have someone hold the back legs together and pull them forward bringing the anus up to you where it is easy to work on. You can also use rope and a tree to hold them up for you. With your left hand, pull the tail down and with a very sharp knife cut deep between the top of the anus and the base of the tail. Then cut a deep outline around the edge of the anus and work the intestine free from the inner pelvic wall. You want it loose enough so that when you pull on it, you can feel it ripping out. But be careful not to pull it out because you don't want any intestines coming out the butt. Once your done, let the legs down. Some people live to take off the penis first but there really isn't much need to.

2: Now you want to carefully make an incision far back on the belly close to the front of the pelic bone. You need to be carefull not to actually cut any of the intestines. Once you get through all the membrates and into the stomach cavity, the intestines will start to squeeze their way out because the body cavity is naturally compressed. They will be warm. As long as your arrow passed through the chest cavity and din't contact any guts or the liver, they should be clean and blood free. Next you need to cut up towards the chest. There are many ways to do this. And if you had a gut hook, this would be much easier because you could start from the top and just cut downwards with the hook. But so long as you don't have the hook, you need to just use the blade. I myself like to hold my hand up onto the back of the blade and place my index finger over the tip. The finger over the tip makes it so the tip doesn't catch on any of the guts. Then you can just run it up intill you hit the brisket. Another method is to inset two fingers and lift the skin up away from the guts and then cut between the two fingers with the knife until you hit the brisket. You do not need to cut the brisket.

3: By now you should be able to see the intestines, the stomach pouch, and the liver. There should be a layer of flesh restricting you from going any further. It is called the diaphram. Cut it out and you will find the chest cavity containing the lungs and heart and lots of coagulated blood. heach your knife up as far as you can into the chest cavity until you hit the front. Then reach your hand up into it. This is the part where many who are not careful badly cut themselves. So so grab the lungs and pull them and then cut them free from the esophogus or whatever it is. Once that is don't everything will rip right out.

4: Rip out the guts started with the lungs and heart. Everything will come right out with it. Then once only the intestine that runs through the pelvis is left, if cut out properly, you should be able to give it one hard yank forward to free it.

And that's basically how I field dress game.

Nic