I've been playing around with BTCJam for the last couple of months. I have about a 10% default rate, but the loans are around 30% so I am netting 20% for the time being.

I really like the idea of p-2-p lending (ala prosper.com), but I am just too worried that the BTC will vanish the instant I put some real numbers into the account. My gut tells me these BTCJam guys are legit, however.