For anyone here who does more than micro .. we just ordered one of these. It's a small accessory you just snap your iPhone in and it allows you to accept credit card payments from clients anywhere. Say you need to meet with a client for them to place an order when you're out on location you can meetup at a starbucks .. take their order .. swipe their card .. grab a caff� mocha .. and be on your way. 

http://www.paywaremobile.com/ .... it's a VeriPhone product so no worries