This looks useful especially with tax season in full swing: Freshbooks has added expense tracking to their online service and it can be done through mobile devices too.

Freshbooks offers online invoicing and time tracking for freelancers. With much of Silicon Valley made up of consultants, lawyers, accountants, and others that bill for their time, this is a type of service that should find plenty of customers.

Users can add or track expenses from anywhere, even on a mobile device, and get them paid faster by including them in the same professional looking invoices that they use to bill for their time. Customers with multiple users accessing the service can also allow staff to see the status of each of their own expenses. In addition, the service helps users with basic expense tracking, such as their rent, car or phone.

There is a free trial at http://www.freshbooks.com