I've just "discovered" Kiva - a non-profit organisation that facilitates micro-financing for developing world entrepreneurs in as little as $25 dollar chunks made via PayPal. Or I could use their wording (which sounds so much better):
"Choose an entrepreneur. Loan as little as $25. Receive updates. Get repaid as the business succeeds."
Their first loans were made in March 2005 and since then they've arranged over $12 million dollars worth of finance to third world entrepreneurs - with an average loan size of just $650 and an incredible default rate of 0.34% (a rate that the loan market in the UK could only fantasize about!!)
Clearly (as usual) I am behind the times as even Oprah has talked about it but don't let that deter you from supporting a start up business now!
EDIT: I should point out that you may not get your money back if the business you select does not succeed.