Action Method I chose this app because I use the desktop and web app daily - "use" is probably an understatement. "Am addicted to" is likely more accurate. The iPhone app syncs with the desktop or web app so that you can reference your to-do list by category or due date exactly as you would on a bigger screen. Cross things off, add, and edit - this app is a perfect extension of the desktop version.

Catch Notes One of my favorite note-taking apps: syncs with the web app and the desktop app, which is awesome. The best feature, however, is the ability to tag every note for easy organizing and searching later. For example, I have "restaurants" tagged for places I want to check out around town, and "blog" tagged for ideas that I should blog about.

Zipcar If you live in a city where Zipcar exists, this is a great app for freelancers and work-from-home folks who also don't have a car - like myself. This opens up the possibilites of where a freelancer can meet clients. Book your appointment or meeting, check to see where the closest car is to you, and then head out to get it done.

PayPal Most of my freelance clients pay via PayPal and this allows access to my account from my phone. I can invoice and accept payments, move money over to my bank account, and always keep up with how much money is in this account.

Harvest Time & Expense Tracker Tracks time spent on projects (by client!), expenses, and is a great, seamless way to invoice clients.