I haven't downloaded and peeked at the source code yet, but the Coding4Fun site has a free time tracking application written in both C# and VB with source code that allows you to track your billable time and project work. Sure there are many applications out there that track your time on projects, but it is always fun to find free VB and C# source code that you can tweak to meet your own needs as well as learn from.
From the article:
“Time and how we use it is a matter of great importance to many people. I am certainly no exception, frequently working on two to five projects at a given time. Whether it's just being curious about how much time you are spending on various classes at school, or billable projects, time tracking can be tedious. Do you use a paper notebook (remember those)? Do you create a spreadsheet in Excel? What about a custom time accounting software package? For this installment of In the Box, I decided it would be good to create a basic time tracking tool to sit quietly in the system tray.
As always, the code for this project is included in a downloadable archive in both C# and Visual Basic versions. The code shown in the article is in C#, though both versions are identical other than syntax differences dictated by language. You will need either the C# or Visual Basic version of Visual Studio 2005 Express Editions. No additional products or tools are required.
The goal of this project was to create a simple application with an uncluttered interface. There are no advanced reporting capabilities, though nothing precludes one from adding them. The first step was to create the notification icon and context menu. Both were dragged from the Toolbox onto the default form (created with the solution). The context menu is attached to the notification icon using the ContextMenuStrip property. Visual Studio automatically offers any context menu strip objects in the drop-down box when setting the property.“
Check it out.