There are lots of options. For now, I’ve settled on iXpenseit. You use the on-phone camera to take a picture of the receipt, then throw away the paper copy (as long as you back up! :-) ). You can do daily expense recording and monthly budgeting, all in the same app. There are bill reminders, PDF reporting, income & cash flow, credit card & checkbook accounting, plus tons of cool charts and graphs to make it look cool. And everything is searchable by the tiniest bit of text, so you can always figure out “what was that expense again?” Find it in the App Store. There’s a lite version (free) and an inexpensive upgrade with more bells & whistles. Got a good option that you like? Please mention it in Comments below.
Another nice feature of iExpenseit is the currency converter. You can use pesos, Euros whatever currency and it wil convert to $$. It updates currency rates via wireless.
You can also add cash or credit expenses and it tracks and separates as needed in the reports.
My favorite travel expense tracking app is TravelBudget. It’s made for international travels, allows you to categorize each expense as business or personal, cash or credit, and then also one of many categories like Food, Transportation, etc. You can then export and email an Excel spreadsheet to yourself. This app has made travel expense reports a breeze for me! The developer has continued to improve this app, and is very responsive to suggestions if there’s some functionality that you’d like to see!
Evernote… syncs seamlessly, lets me keep track of pics, audio, text… and it’s already on my phone.