Using OPM to purchase our first property

We found a great deal the other day that we wanted to move on. Our first reaction was "we can scrape up the $10,000 we need for a down payment on this property from our savings accounts." Then, after the smoke setteled, I realized what we had done and I was very dissapointed with myself. We got so excited about finding our first property that we wanted to make the move right now, instead of taking a step back and thinking how could we use other people's money to buy this for us... We came up with the plan of finding investors (family, friends, etc.) to invest a minimum of $5000 with us to be repaid over a period of 3 years at 10% interest. Stocks and bond funds on the good side pay 6 to 7% in today's market. So we thought this would be a great way to attract potential investors.

My question now is what kind of a contract would I need between ourselves and the investors? Should the contract be backed by a percentage of the property purchase price, should we create a "general partnership agreement". What about having the contract notarized? Maybe just a good old fashion hand shake would suffice. I am thinking all we would need might be just a promissary note secured by the property some how. If anybody has been down this road before any information you might have would be extremely helpful.

Thanks in advance,

Eric and Kelly