Need to track how you spend your time? Check out Toggl (link here), a cool, simple application that allows you to do just that. Features single-click tracking, easy task-switching and report creation.
Use it to assist your billing efforts with its very simple interface, or use it to help you refocus your efforts on the most important activities within your day or across weeks. Download Toggl desktop, or use as a website or small browser pop-up. Works on your desktop in Windows, Mac and Linux environments or on the go with iPhone and Android systems. Toggl has gadgets to add timers to your desktop and web browsing, as well as tools for iGoogle and Gmail.
Toggl is free for five users, but adds a few features (earnings tracking, plan-ahead tasks, branded reports, and Basecamp, iCal and RSS integration) and users if you choose, with different plans and costs depending on how many users.
If you like them simple, and I do like them simple, Toggl is hard to beat.