I too am not a lawyer but another possible way to do this, to the best of my knowledge:
File a provisional patent application (with maximum disclosure) with the USPTO - this will give you a priority date on official, government record. Make sure you obtain a certified copy from them. Then let it lapse (i.e. don't convert to a full application within the stipulated time period of one year).
I guess that should do it.
Disclaimer (again): I'm not a lawyer :-)
Edit: Added:
I don't know how effective/legally valid this is today, but there also used to be something called a sealed cover method. You disclose the full invention on paper, get a government approved notary to notarise it, seal it up in an envelop and send it as a registered mail to yourself. On receipt, don't open it - just keep it safe. In case of any later dispute, you'll have two government agencies establishing your date of invention. - HTH
2nd Edit: Added: The sealed cover method, if valid, would probably be the least expensive one. :-)
File a provisional patent application (with maximum disclosure) with the USPTO - this will give you a priority date on official, government record. Make sure you obtain a certified copy from them. Then let it lapse (i.e. don't convert to a full application within the stipulated time period of one year).
I guess that should do it.
Disclaimer (again): I'm not a lawyer :-)
Edit: Added: I don't know how effective/legally valid this is today, but there also used to be something called a sealed cover method. You disclose the full invention on paper, get a government approved notary to notarise it, seal it up in an envelop and send it as a registered mail to yourself. On receipt, don't open it - just keep it safe. In case of any later dispute, you'll have two government agencies establishing your date of invention. - HTH
2nd Edit: Added: The sealed cover method, if valid, would probably be the least expensive one. :-)