Micropayments were a $1 billion industry in 2009. If they hope to grow in 2010, these types of transactions need to be made easier. One of the slickest implementations was a application from Paypal, which lets users "bump" their iPhones or iPods to authorize a transaction between accounts. Owe a friend for pizza? Click your phones together and the debt's resolved. A startup called Venmo (now in private beta) goes even one step further. Friends can issue payments with text messages or create a special list of people who they trust, who are then allowed to pull money from their account at will.