You can write your own will, I believe it just has to be witnessed, then notarized. Here are some good pointers on one: http://funadvice.com/r/14spibh9sro.
Probably best to talk to a lawyer anyways tho once you have it written out and have them double check it will stand up in court if need be.
youll need to talk to your lawyer about the will, but it could also be a written statement with "witnesses" (who should not be a part of the will or they will be disowned) with signatures etc.
but your lawyer will gfill you in on the details :)
It costs money to make a will with a lawyer, but I am told in some places its cheaper (and perfectly legal) to buy a kit for making a will and doing it yourself