Yesterday I published some software that I'm hoping people will like. I'm calling it GTime. It's an application that runs on Adobe® AIR™ and works with Google™ Spreadsheets. It's fairly self explanatory; you login to your Google account, create a new timesheet, and that timesheet will sit on Google's servers as a spreadsheet. GTime features a simple start / pause / stop timer that allows you to easily and accurately track your time (something every time tracking software should have), and it will insert that time record into the Google spreadsheet.
In order to do this, I made an Actionscript API to Google's services. This API will work with the Google List Data, Documents, and Spreadsheets services. I'm not completely sure what I plan on doing with the API, I may open source it, but I haven't decided yet.
You can try this utility at Google Time Tracking.